/* ==========================================================================
Mod's Engineering Mathematics — shared styles
========================================================================== */
:root{
--paper:#f5f2ea; --paper-2:#ece7da; --card:#fbf9f4;
--ink:#172029; --ink-2:#4a5560; --ink-3:#737d86;
--rule:#d9d2c1; --grid:rgba(23,32,41,.055);
--accent:#c94f18; --accent-ink:#ffffff; --signal:#1f5fa8; --ok:#2f7d4f;
--shadow:0 1px 0 rgba(23,32,41,.06), 0 8px 24px -12px rgba(23,32,41,.18);
--serif:"Trirong","IBM Plex Sans Thai",Georgia,serif;
--sans:"IBM Plex Sans Thai",system-ui,sans-serif;
--mono:"IBM Plex Mono",ui-monospace,monospace;
--max:1120px;
}
@media (prefers-color-scheme: dark){
:root:not([data-theme="light"]){
--paper:#11171d; --paper-2:#161e26; --card:#18212a;
--ink:#ece8df; --ink-2:#b4bcc3; --ink-3:#8a949c;
--rule:#2a3540; --grid:rgba(236,232,223,.045);
--accent:#f07a3e; --accent-ink:#11171d; --signal:#6aa6e8; --ok:#5fbf86;
--shadow:0 1px 0 rgba(0,0,0,.3), 0 10px 30px -14px rgba(0,0,0,.6);
}
}
:root[data-theme="dark"]{
--paper:#11171d; --paper-2:#161e26; --card:#18212a;
--ink:#ece8df; --ink-2:#b4bcc3; --ink-3:#8a949c;
--rule:#2a3540; --grid:rgba(236,232,223,.045);
--accent:#f07a3e; --accent-ink:#11171d; --signal:#6aa6e8; --ok:#5fbf86;
--shadow:0 1px 0 rgba(0,0,0,.3), 0 10px 30px -14px rgba(0,0,0,.6);
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{scroll-behavior:smooth;scroll-padding-top:76px}
@media (prefers-reduced-motion: reduce){html{scroll-behavior:auto}}
body{
margin:0;background:var(--paper);color:var(--ink);
font-family:var(--sans);font-size:17px;line-height:1.7;
background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);
background-size:24px 24px;-webkit-font-smoothing:antialiased;
}
a{color:inherit}
img,svg{display:block;max-width:100%}
.wrap{max-width:var(--max);margin:0 auto;padding:0 16px}
@media (min-width:720px){.wrap{padding:0 32px}}
.mono{font-family:var(--mono);font-size:.8rem;letter-spacing:.02em}
.eyebrow{font-family:var(--mono);font-size:.78rem;color:var(--accent);letter-spacing:.04em;margin:0 0 14px}
h1,h2,h3{font-family:var(--serif);line-height:1.3;margin:0;font-weight:700;letter-spacing:-.005em}
h2{font-size:clamp(1.6rem,3.6vw,2.3rem)}
.lede{color:var(--ink-2);max-width:62ch}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px}
.skip{position:absolute;left:12px;top:-60px;z-index:50;background:var(--ink);color:var(--paper);padding:8px 14px;border-radius:8px;text-decoration:none}
.skip:focus{top:10px}
/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;gap:8px;padding:11px 18px;border-radius:8px;border:1px solid transparent;
font:600 .95rem/1.1 var(--sans);text-decoration:none;cursor:pointer;transition:transform .15s,background .15s,border-color .15s}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--accent);color:var(--accent-ink)}
.btn-primary:hover{background:color-mix(in srgb,var(--accent) 88%,var(--ink))}
.btn-ghost{border-color:var(--rule);background:var(--card);color:var(--ink)}
.btn-ghost:hover{border-color:var(--ink-3)}
.btn-sm{padding:8px 13px;font-size:.85rem;white-space:nowrap}
.icon-btn{width:38px;height:38px;border-radius:8px;border:1px solid var(--rule);background:var(--card);color:var(--ink-2);
cursor:pointer;display:grid;place-items:center;flex:none;padding:0}
.icon-btn svg{width:18px;height:18px}
/* ---------- header / nav ---------- */
.nav{position:sticky;top:0;z-index:30;background:color-mix(in srgb,var(--paper) 90%,transparent);
backdrop-filter:saturate(1.2) blur(8px);-webkit-backdrop-filter:saturate(1.2) blur(8px);border-bottom:1px solid var(--rule)}
.nav .wrap{display:flex;align-items:center;gap:10px;height:62px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:600;white-space:nowrap;min-width:0}
.brand-mark{width:30px;height:30px;border-radius:7px;background:#172029;display:grid;place-items:center;flex:none}
.brand-mark svg{width:22px;height:22px}
.brand span{line-height:1.15;font-size:.95rem}
.brand small{display:block;font-family:var(--mono);font-weight:400;font-size:.68rem;color:var(--ink-3);line-height:1.2}
.nav-yt{margin-left:auto}
.nav-links a{text-decoration:none;color:var(--ink-2);white-space:nowrap}
.nav-links a:hover{color:var(--ink)}
.nav-links a[aria-current="page"]{color:var(--ink);font-weight:600}
.nav-yt-panel{display:none}
.nav-links a.nav-sub{display:none}
/* desktop */
@media (min-width:1900px){
.nav .wrap{max-width:1300px}
.nav-links{display:flex;gap:16px;margin-left:auto;font-size:.92rem}
.nav-links a[aria-current="page"]{box-shadow:inset 0 -2px 0 var(--accent)}
.nav-yt{margin-left:8px}
.menu-btn{display:none}
}
/* mobile: hamburger */
@media (max-width:1899px){
.menu-btn{display:grid;gap:4px;align-content:center;justify-items:center}
.menu-btn span{display:block;width:18px;height:2px;border-radius:2px;background:var(--ink);transition:transform .2s,opacity .2s}
.nav[data-open] .menu-btn span:nth-child(1){transform:translateY(6px) rotate(45deg)}
.nav[data-open] .menu-btn span:nth-child(2){opacity:0}
.nav[data-open] .menu-btn span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}
.nav-links{display:none;position:fixed;left:0;right:0;top:62px;max-height:calc(100dvh - 62px);overflow:auto;
flex-direction:column;background:var(--paper);border-bottom:1px solid var(--rule);box-shadow:0 18px 30px -18px rgba(0,0,0,.35);padding:8px 16px 20px}
.nav[data-open] .nav-links{display:flex}
.nav-links a{padding:15px 4px;font-size:1.08rem;border-bottom:1px solid var(--rule);color:var(--ink)}
.nav-links a[aria-current="page"]{color:var(--accent)}
.nav-yt-panel{display:block;border-bottom:0!important;color:var(--accent)!important;font-weight:600}
.nav-links a.nav-sub{display:block;padding:11px 4px 11px 24px;font-size:.98rem;color:var(--ink-2);position:relative}
.nav-links a.nav-sub::before{content:"↳";position:absolute;left:4px;color:var(--ink-3)}
}
@media (max-width:440px){
.brand small{display:none}
.brand span{font-size:.88rem}
.nav-yt{display:none}
.menu-btn{margin-left:auto}
.search-btn{margin-left:auto}
.theme-toggle + .menu-btn{margin-left:0}
}
/* ---------- site search dialog (assets/site.js) ---------- */
.search-dlg{width:min(680px,calc(100vw - 32px));max-height:min(78dvh,720px);margin:9vh auto auto;padding:0;border:1px solid var(--rule);border-radius:12px;
background:var(--paper);color:var(--ink);box-shadow:0 24px 60px -20px rgba(0,0,0,.45);overflow:hidden;flex-direction:column}
.search-dlg[open]{display:flex}
.search-dlg::backdrop{background:rgba(17,23,29,.45);backdrop-filter:blur(2px)}
.search-bar{display:flex;align-items:center;gap:10px;padding:12px 14px;border-bottom:1px solid var(--rule);background:var(--card)}
.search-bar > svg{width:20px;height:20px;flex:none;color:var(--ink-3)}
.search-bar input{flex:1;min-width:0;border:0;outline:0;background:transparent;color:var(--ink);font:inherit;font-size:1.05rem;padding:6px 0}
.search-bar input::-webkit-search-cancel-button{display:none}
.search-close{flex:none;font-family:var(--mono);font-size:.72rem;padding:4px 8px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink-2);cursor:pointer}
.search-results{list-style:none;margin:0;padding:6px;overflow-y:auto;flex:1;min-height:0}
.search-results:empty{display:none}
.search-results a{display:block;text-decoration:none;color:inherit;border-radius:8px;padding:9px 12px}
.search-results a[aria-selected="true"],.search-results a:hover{background:color-mix(in srgb,var(--accent) 11%,transparent)}
.search-results a[aria-selected="true"]{box-shadow:inset 3px 0 0 var(--accent)}
.search-results b{display:block;font-weight:600;line-height:1.4}
.search-results small{display:block;font-family:var(--mono);font-size:.72rem;color:var(--ink-3);margin-top:2px}
.search-results span{display:block;font-size:.86rem;color:var(--ink-2);line-height:1.5;margin-top:3px}
.search-results mark{background:color-mix(in srgb,var(--accent) 26%,transparent);color:inherit;border-radius:2px}
.search-subs{list-style:none;margin:0 0 4px 14px;padding:0 0 0 10px;border-left:1px solid var(--rule)}
.search-subs a{padding:5px 10px;font-size:.88rem;color:var(--ink-2)}
.search-subs a::before{content:"# ";color:var(--ink-3);font-family:var(--mono)}
.search-status{margin:0;padding:9px 16px;font-size:.8rem;color:var(--ink-3);border-top:1px solid var(--rule)}
.search-results:empty + .search-status{border-top:0;padding:14px 16px}
@media (max-width:600px){.search-dlg{margin-top:12px;max-height:calc(100dvh - 24px)}}
/* ---------- footer ---------- */
.site-footer{border-top:1px solid var(--rule);background:var(--paper-2);color:var(--ink-2);font-size:.92rem;margin-top:0}
.footer-grid{display:grid;gap:28px;padding-top:40px;padding-bottom:28px}
@media (min-width:720px){.footer-grid{grid-template-columns:2fr 1fr 1fr}}
.footer-grid p{margin:10px 0 0}
.footer-grid nav{display:flex;flex-direction:column;gap:6px}
.footer-grid nav b{color:var(--ink-3);font-weight:500;margin-bottom:4px}
.footer-grid nav a{text-decoration:none}
.footer-grid nav a:hover{color:var(--ink)}
.footer-base{display:flex;flex-wrap:wrap;gap:10px 24px;justify-content:space-between;padding-top:16px;padding-bottom:32px;border-top:1px solid var(--rule);color:var(--ink-3);font-size:.85rem}
.footer-base a{text-decoration:none}
/* ---------- sections ---------- */
section.block{padding:72px 0}
@media (min-width:900px){section.block{padding:100px 0}}
.sec-head{display:grid;gap:12px;margin-bottom:36px}
.sec-head-row{display:flex;flex-wrap:wrap;align-items:end;justify-content:space-between;gap:16px;margin-bottom:28px}
.band{background:var(--paper-2);border-block:1px solid var(--rule)}
/* ==========================================================================
HOME
========================================================================== */
.hero{padding:56px 0 40px}
@media (min-width:900px){.hero{padding:84px 0 64px}}
.hero-grid{display:grid;gap:40px;align-items:center}
@media (min-width:900px){.hero-grid{grid-template-columns:1.05fr .95fr;gap:56px}}
.hero h1{font-size:clamp(2.3rem,6.2vw,4rem);line-height:1.18}
.hero h1 em{font-style:normal;color:var(--accent)}
.hero .lede{font-size:1.08rem;margin:20px 0 28px}
.cta-row{display:flex;flex-wrap:wrap;gap:12px}
.hero-meta{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:28px;color:var(--ink-3)}
.hero-meta span::before{content:"▸ ";color:var(--accent)}
.scope{background:var(--card);border:1px solid var(--rule);border-radius:14px;box-shadow:var(--shadow);padding:16px 16px 12px;margin:0}
.scope-head{display:flex;justify-content:space-between;color:var(--ink-3);margin-bottom:8px}
.scope-head b{color:var(--ink);font-weight:500}
.scope svg{width:100%;height:auto}
.scope .axis{stroke:var(--ink-3);stroke-width:1}
.scope .gridline{stroke:var(--rule);stroke-width:1}
.scope .ref{stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:4 4}
.scope .resp{fill:none;stroke:var(--accent);stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}
.scope .lbl{font-family:var(--mono);font-size:11px;fill:var(--ink-3)}
.scope .ann{font-family:var(--mono);font-size:11px;fill:var(--signal)}
.scope .ann-line{stroke:var(--signal);stroke-width:1}
.scope-ctrl{display:flex;align-items:center;gap:12px;margin-top:6px;color:var(--ink-2)}
.scope-ctrl input{flex:1;accent-color:var(--accent)}
.scope-ctrl output{min-width:5.2ch;text-align:right;color:var(--ink)}
.scope-note{margin:6px 0 0;color:var(--ink-3);font-size:.82rem}
.ticker{border-block:1px solid var(--rule);background:var(--paper-2);overflow:hidden;white-space:nowrap}
.ticker-track{display:inline-flex;gap:44px;padding:12px 0;animation:tick 40s linear infinite;color:var(--ink-2)}
.ticker-track span{font-family:var(--mono);font-size:.9rem}
@keyframes tick{to{transform:translateX(-50%)}}
@media (prefers-reduced-motion: reduce){.ticker-track{animation:none}}
/* learning path */
.path{position:relative;display:grid;gap:14px}
@media (min-width:900px){.path{grid-template-columns:repeat(4,1fr);gap:0;padding-bottom:58px}}
.node{position:relative;text-align:left;cursor:pointer;display:flex;flex-direction:column;align-items:flex-start;
background:var(--card);border:1.5px solid var(--ink);border-radius:10px;padding:18px 18px 16px;color:var(--ink);font:inherit;
transition:transform .18s,box-shadow .18s,border-color .18s}
.node:hover,.node:focus-visible{transform:translateY(-3px);box-shadow:var(--shadow);outline:none;border-color:var(--accent)}
.node[aria-current="true"]{border-color:var(--accent);box-shadow:0 0 0 3px color-mix(in srgb,var(--accent) 22%,transparent)}
.node .num{font-family:var(--mono);font-size:.75rem;color:var(--accent)}
.node h3{font-family:var(--sans);font-weight:600;font-size:1.05rem;margin:6px 0 2px}
.node .th{font-size:.88rem;color:var(--ink-2);margin:0 0 10px}
.node .why{font-size:.88rem;color:var(--ink-2);margin:0;padding-top:10px;border-top:1px dashed var(--rule)}
.node .go{display:inline-block;margin-top:auto;padding-top:12px;font-family:var(--mono);font-size:.75rem;color:var(--signal)}
.node:not(:last-of-type)::after{content:"";position:absolute;left:50%;bottom:-14px;width:1.5px;height:14px;background:var(--ink)}
.node:not(:last-of-type)::before{content:"";position:absolute;left:calc(50% - 5px);bottom:-15px;border:5px solid transparent;border-top:6px solid var(--ink);border-bottom:0}
@media (min-width:900px){
.node{margin-right:28px}
.node:last-of-type{margin-right:0}
.node:not(:last-of-type)::after{left:auto;right:-28px;top:50%;bottom:auto;width:28px;height:1.5px}
.node:not(:last-of-type)::before{left:auto;right:-29px;top:calc(50% - 5px);bottom:auto;border:5px solid transparent;border-left:7px solid var(--ink);border-right:0}
.feedback{position:absolute;left:12.5%;right:12.5%;bottom:0;height:46px;border:1.5px dashed var(--ink-3);border-top:0;border-radius:0 0 12px 12px;pointer-events:none}
.feedback::before{content:"";position:absolute;left:-6px;top:-8px;border:5px solid transparent;border-bottom:7px solid var(--ink-3);border-top:0}
.feedback span{position:absolute;left:50%;bottom:-11px;transform:translateX(-50%);background:var(--paper);padding:0 10px;font-family:var(--mono);font-size:.75rem;color:var(--ink-3);white-space:nowrap}
}
@media (max-width:899px){.feedback{display:none}}
/* player */
.player-grid{display:grid;gap:20px}
@media (min-width:900px){.player-grid{grid-template-columns:300px 1fr;gap:28px}}
.tabs{display:flex;gap:8px;overflow-x:auto;padding-bottom:4px;scrollbar-width:thin}
@media (min-width:900px){.tabs{flex-direction:column;overflow:visible}}
.tab{flex:none;text-align:left;cursor:pointer;font:inherit;color:var(--ink-2);background:transparent;border:1px solid var(--rule);
border-radius:9px;padding:10px 14px;display:flex;gap:12px;align-items:baseline;transition:background .15s,border-color .15s,color .15s}
.tab .mono{color:var(--ink-3)}
.tab:hover{border-color:var(--ink-3);color:var(--ink)}
.tab[aria-selected="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.tab[aria-selected="true"] .mono{color:var(--accent)}
.tab b{font-weight:600;font-size:.95rem}
.screen{position:relative;aspect-ratio:16/9;border-radius:12px;overflow:hidden;background:#0f151b;border:1px solid var(--rule);box-shadow:var(--shadow)}
.screen iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.facade{position:absolute;inset:0;display:flex;flex-direction:column;justify-content:space-between;padding:22px;color:#ece8df;
background:radial-gradient(120% 90% at 85% 10%,rgba(212,86,29,.28),transparent 60%),
linear-gradient(rgba(236,232,223,.05) 1px,transparent 1px) 0 0/24px 24px,
linear-gradient(90deg,rgba(236,232,223,.05) 1px,transparent 1px) 0 0/24px 24px,#0f151b}
.facade .f-eq{font-family:var(--mono);font-size:clamp(.9rem,2.4vw,1.25rem);color:#f0a274}
.facade h3{font-size:clamp(1.3rem,3.4vw,2rem);color:#fff}
.facade p{margin:4px 0 0;color:#b4bcc3;font-size:.95rem}
.play{display:inline-flex;align-items:center;gap:10px;align-self:flex-start;cursor:pointer;background:#f07a3e;color:#11171d;border:0;
border-radius:999px;padding:12px 20px 12px 14px;font:600 1rem var(--sans)}
.play i{width:30px;height:30px;border-radius:50%;background:#11171d;display:grid;place-items:center}
.play i::after{content:"";border-left:10px solid #f07a3e;border-top:6px solid transparent;border-bottom:6px solid transparent;margin-left:3px}
.play:hover{background:#ff8c52}
.below-screen{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;margin:12px 0 0;color:var(--ink-3)}
.below-screen a{color:var(--signal);text-decoration:none}
.below-screen a:hover{text-decoration:underline}
.more{margin-top:36px;padding:20px 22px;border:1px dashed var(--ink-3);border-radius:12px;display:flex;flex-wrap:wrap;gap:16px;align-items:center;justify-content:space-between}
.more p{margin:0;color:var(--ink-2);max-width:60ch}
/* topic cards (home + learn hub) */
.topic-grid{display:grid;gap:14px}
@media (min-width:640px){.topic-grid{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1000px){.topic-grid{grid-template-columns:repeat(4,1fr)}}
.topic-card{display:flex;flex-direction:column;gap:4px;text-decoration:none;background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:20px;
transition:transform .18s,border-color .18s,box-shadow .18s}
.topic-card:hover{transform:translateY(-3px);border-color:var(--accent);box-shadow:var(--shadow)}
.tc-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px}
.tc-sym{width:42px;height:42px;border-radius:10px;background:var(--ink);color:var(--paper);display:grid;place-items:center;font:500 1.25rem var(--serif)}
.tc-num{font-family:var(--mono);font-size:.78rem;color:var(--ink-3)}
.topic-card b{font-size:1.08rem;line-height:1.35}
.tc-en{font-family:var(--mono);font-size:.76rem;color:var(--ink-3)}
.tc-sum{color:var(--ink-2);font-size:.9rem;margin-top:6px}
.tc-foot{display:flex;justify-content:space-between;gap:8px;margin-top:auto;padding-top:14px;font-family:var(--mono);font-size:.76rem}
.tc-go{color:var(--signal)}
.tc-vid{color:var(--accent)}
/* home about teaser */
.about-grid{display:grid;gap:36px}
@media (min-width:900px){.about-grid{grid-template-columns:340px 1fr;gap:56px;align-items:center}}
.idcard{background:var(--card);border:1px solid var(--rule);border-radius:14px;box-shadow:var(--shadow);overflow:hidden;align-self:start}
.idcard-top{background:#172029;color:#ece8df;padding:26px 22px}
.monogram{width:72px;height:72px;border-radius:12px;border:1.5px solid #f07a3e;display:grid;place-items:center;font-family:var(--serif);font-size:1.6rem;color:#f07a3e;margin-bottom:16px}
.idcard-top h3{font-size:1.3rem}
.idcard-top p{margin:2px 0 0;font-family:var(--mono);font-size:.75rem;opacity:.7}
.idcard dl{margin:0;padding:8px 22px 18px}
.idcard dl div{padding:12px 0;border-bottom:1px solid var(--rule)}
.idcard dl div:last-child{border-bottom:0}
.idcard dt{font-family:var(--mono);font-size:.72rem;color:var(--ink-3);letter-spacing:.06em}
.idcard dd{margin:2px 0 0;font-size:.95rem}
.quote{font-family:var(--serif);font-size:clamp(1.3rem,2.8vw,1.8rem);line-height:1.5;margin:0 0 28px;padding-left:20px;border-left:3px solid var(--accent)}
/* contact link cards */
.links{display:grid;gap:14px}
@media (min-width:760px){.links{grid-template-columns:repeat(3,1fr)}}
.linkcard{display:flex;flex-direction:column;gap:6px;text-decoration:none;background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:22px;
transition:transform .18s,border-color .18s,box-shadow .18s}
.linkcard:hover{transform:translateY(-3px);border-color:var(--ink-3);box-shadow:var(--shadow)}
.linkcard .ic{width:40px;height:40px;border-radius:10px;display:grid;place-items:center;margin-bottom:8px}
.linkcard .ic svg{width:22px;height:22px}
.linkcard b{font-size:1.05rem}
.linkcard span{color:var(--ink-2);font-size:.9rem}
.linkcard .mono{color:var(--signal);margin-top:auto;padding-top:8px}
.ic-yt{background:#ff0000;color:#fff}
.ic-fb{background:#1877f2;color:#fff}
.ic-uni{background:#172029;color:#ece8df}
/* ==========================================================================
ABOUT / PROFILE
========================================================================== */
.profile{padding:48px 0 24px}
@media (min-width:900px){.profile{padding:72px 0 32px}}
.profile-grid{display:grid;gap:28px;align-items:center}
@media (min-width:820px){.profile-grid{grid-template-columns:auto 1fr}}
.avatar{width:132px;height:132px;border-radius:28px;background:#172029;display:grid;place-items:center;position:relative;box-shadow:var(--shadow)}
.avatar span{font:700 2.6rem var(--serif);color:#f07a3e}
.avatar::after{content:"";position:absolute;right:-6px;bottom:-6px;width:28px;height:28px;border-radius:50%;background:var(--ok);border:4px solid var(--paper)}
.profile h1{font-size:clamp(1.9rem,4.6vw,3rem)}
.profile .en{font-family:var(--mono);font-size:.82rem;color:var(--ink-3);margin:4px 0 12px;letter-spacing:.04em}
.profile .role{margin:0;color:var(--ink-2);max-width:62ch}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:16px 0 0;padding:0;list-style:none}
.chips li,.chip{font-size:.84rem;padding:5px 12px;border-radius:999px;border:1px solid var(--rule);background:var(--card);color:var(--ink-2)}
.profile .cta-row{margin-top:22px}
.bento{display:grid;gap:14px;grid-template-columns:repeat(2,1fr)}
@media (min-width:900px){.bento{grid-template-columns:repeat(4,1fr)}}
.tile{background:var(--card);border:1px solid var(--rule);border-radius:16px;padding:20px;box-shadow:var(--shadow);min-width:0}
.tile .big{font:700 clamp(1.8rem,4vw,2.4rem)/1.1 var(--serif)}
.tile .big small{font-size:.5em;font-family:var(--sans);font-weight:500;color:var(--ink-3);margin-left:4px}
.tile p{margin:6px 0 0;color:var(--ink-2);font-size:.9rem}
.tile-dark{background:#172029;color:#ece8df;border-color:#172029}
.tile-dark p{color:#b4bcc3}
.span-2{grid-column:span 2}
@media (min-width:900px){.span-r2{grid-row:span 2}}
/* now + feed */
.now-card{grid-column:1/-1}
@media (min-width:900px){.now-card{grid-column:span 2;grid-row:span 2}}
.now-head{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px}
.now-head h2{font-size:1.25rem;display:flex;align-items:center;gap:10px}
.pulse{width:10px;height:10px;border-radius:50%;background:var(--ok);box-shadow:0 0 0 0 color-mix(in srgb,var(--ok) 60%,transparent);animation:pulse 2s infinite}
@keyframes pulse{70%{box-shadow:0 0 0 10px transparent}100%{box-shadow:0 0 0 0 transparent}}
@media (prefers-reduced-motion: reduce){.pulse{animation:none}}
.now-list{list-style:none;margin:0;padding:0;display:grid;gap:10px}
.now-list li{display:flex;gap:12px;align-items:flex-start;padding:12px 14px;border-radius:12px;background:var(--paper);border:1px solid var(--rule);font-size:.95rem}
.now-ic{font-size:1.15rem;line-height:1.5}
.feed-wrap{max-width:760px}
.filters{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 20px}
.filters button{font:500 .85rem var(--sans);padding:6px 14px;border-radius:999px;border:1px solid var(--rule);background:var(--card);color:var(--ink-2);cursor:pointer}
.filters button[aria-pressed="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.feed{list-style:none;margin:0;padding:0;position:relative}
.feed::before{content:"";position:absolute;left:7px;top:8px;bottom:8px;width:2px;background:var(--rule)}
.post{position:relative;padding:0 0 22px 34px}
.post::before{content:"";position:absolute;left:0;top:7px;width:16px;height:16px;border-radius:50%;background:var(--paper);border:3px solid var(--accent)}
.post-meta{display:flex;flex-wrap:wrap;gap:10px;align-items:center;font-size:.82rem;color:var(--ink-3)}
.tag{font-family:var(--mono);font-size:.72rem;padding:2px 9px;border-radius:999px;background:color-mix(in srgb,var(--accent) 14%,transparent);color:var(--accent)}
.post p{margin:6px 0 0;background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px 16px}
.post-link{display:inline-block;margin-top:8px;font-size:.88rem;color:var(--signal);text-decoration:none}
.post-link:hover{text-decoration:underline}
.post[hidden]{display:none}
.feed-more{margin-top:4px}
/* work cards */
.work-grid{display:grid;gap:14px}
@media (min-width:720px){.work-grid{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1040px){.work-grid{grid-template-columns:repeat(3,1fr)}}
.work{display:flex;flex-direction:column;gap:8px;background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:22px}
.work .kind{font-family:var(--mono);font-size:.74rem;color:var(--accent)}
.work h3{font-family:var(--sans);font-size:1.08rem;font-weight:600}
.work p{margin:0;color:var(--ink-2);font-size:.92rem}
.work .status{margin-top:auto;padding-top:10px;font-family:var(--mono);font-size:.74rem;color:var(--ink-3)}
.work .status b{color:var(--ok);font-weight:500}
.work a{color:var(--signal);font-size:.88rem;text-decoration:none}
.two-col{display:grid;gap:28px}
@media (min-width:900px){.two-col{grid-template-columns:1fr 1fr;gap:48px}}
.principles{display:grid;gap:12px;margin:0;padding:0;list-style:none;counter-reset:p}
.principles li{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:16px 18px}
.principles h3{font-family:var(--sans);font-size:1rem;font-weight:600;margin:0 0 2px}
.principles p{margin:0;font-size:.9rem;color:var(--ink-2)}
.principles .mono{color:var(--accent)}
.life{display:grid;gap:14px}
@media (min-width:720px){.life{grid-template-columns:repeat(3,1fr)}}
.life .tile{display:flex;flex-direction:column;gap:6px}
.life .emo{font-size:1.8rem;line-height:1}
.life h3{font-family:var(--sans);font-size:1.02rem;font-weight:600}
/* about credentials */
.cred-grid{display:grid;gap:14px}
@media (min-width:720px){.cred-grid{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1040px){.cred-grid{grid-template-columns:1.1fr 1.1fr .9fr}}
.cred h3{font-family:var(--sans);font-size:1.02rem;font-weight:600;margin-bottom:12px}
.cred h3 small{font-family:var(--mono);font-size:.72rem;font-weight:500;color:var(--accent);margin-left:6px}
.cred-list{list-style:none;margin:0;padding:0;display:grid;gap:14px}
.cred-list li{display:flex;flex-direction:column;gap:2px;padding-top:14px;border-top:1px solid var(--rule)}
.cred-list li:first-child{padding-top:0;border-top:0}
.cred-list b{font-weight:600;font-size:.96rem}
.cred-list span{color:var(--ink-2);font-size:.9rem}
.cred-list .cred-en{color:var(--ink-3);font-size:.82rem}
.cred-list a{font-family:var(--mono);font-size:.88rem;color:var(--signal)}
.cred-list li.cred-id{display:grid;grid-template-columns:38px minmax(0,1fr);column-gap:12px;row-gap:2px;align-items:center}
.cred-id .cred-ic{grid-row:span 2;width:38px;height:38px;border-radius:10px;display:grid;place-items:center;background:var(--paper-2);border:1px solid var(--rule);color:var(--ink-2)}
.cred-id .cred-ic svg{width:22px;height:22px}
.cred-id a{white-space:nowrap}
.cred-id .cred-ic-orcid{background:transparent;border:0}
.cred-id .cred-ic-orcid svg{width:32px;height:32px}
/* about photos */
.avatar img{display:block;width:100%;height:100%;object-fit:cover;border-radius:inherit}
@media (min-width:820px){.profile .avatar{width:160px;height:160px;border-radius:32px}}
.ph{margin:0;min-width:0}
.ph img{display:block;width:100%;height:auto;border-radius:14px;border:1px solid var(--rule);background:var(--paper-2);box-shadow:var(--shadow)}
.ph figcaption{margin-top:10px;font-size:.88rem;line-height:1.55;color:var(--ink-2)}
.ph figcaption a,.ph figcaption .nw{white-space:nowrap}
.class-photos{margin-top:48px}
.class-photos h3{font-family:var(--sans);font-size:1.02rem;font-weight:600;margin:6px 0 18px}
.ph-row{display:grid;gap:14px;grid-auto-flow:column;grid-auto-columns:82%;overflow-x:auto;scroll-snap-type:x mandatory;padding-bottom:8px;scrollbar-width:thin}
.ph-row .ph{scroll-snap-align:start}
@media (min-width:720px){.ph-row{grid-auto-flow:row;grid-auto-columns:auto;grid-template-columns:repeat(3,1fr);overflow:visible;padding-bottom:0}}
.trip{display:grid;gap:14px;grid-template-columns:1fr 1fr;margin-bottom:14px}
.trip-text{grid-column:1/-1;display:flex;flex-direction:column;gap:16px;justify-content:space-between}
.trip-text > div{display:flex;flex-direction:column;gap:6px}
.trip-text .trip-links{font-size:.88rem;color:var(--ink-3);padding-top:12px;border-top:1px solid var(--rule)}
.trip-text .kind{font-family:var(--mono);font-size:.74rem;color:var(--accent)}
.trip-text h3{font-family:var(--sans);font-size:1.02rem;font-weight:600}
.trip-text p{margin:0;color:var(--ink-2);font-size:.92rem}
@media (min-width:900px){.trip{grid-template-columns:1.1fr 1fr 1fr;align-items:start}.trip-text{grid-column:auto;align-self:stretch}}
/* bio kit */
.biokit{background:var(--card);border:1px solid var(--rule);border-radius:16px;box-shadow:var(--shadow);overflow:hidden}
.bio-tabs{display:flex;gap:4px;padding:8px;border-bottom:1px solid var(--rule);background:var(--paper-2);overflow-x:auto}
.bio-tabs button{font:500 .88rem var(--sans);padding:8px 14px;border-radius:8px;border:0;background:transparent;color:var(--ink-2);cursor:pointer;white-space:nowrap}
.bio-tabs button[aria-selected="true"]{background:var(--card);color:var(--ink);box-shadow:var(--shadow)}
.bio-panel{padding:20px 22px}
.bio-panel[hidden]{display:none}
.bio-text{margin:0 0 16px;white-space:pre-line}
.bio-actions{display:flex;flex-wrap:wrap;gap:10px}
.copied{color:var(--ok);font-size:.88rem;align-self:center}
/* ==========================================================================
LEARN
========================================================================== */
.page-head{padding:48px 0 28px}
@media (min-width:900px){.page-head{padding:72px 0 36px}}
.page-head h1{font-size:clamp(2rem,5vw,3.2rem)}
.page-head .lede{margin:16px 0 0;font-size:1.05rem}
.crumbs{display:flex;flex-wrap:wrap;gap:6px;font-family:var(--mono);font-size:.76rem;color:var(--ink-3);margin:0 0 18px;padding:0;list-style:none}
.crumbs li+li::before{content:"/";margin-right:6px}
.crumbs a{text-decoration:none}
.crumbs a:hover{color:var(--ink)}
.book-grid{display:grid;gap:14px}
@media (min-width:760px){.book-grid{grid-template-columns:repeat(2,1fr)}}
.book{display:grid;grid-template-columns:72px 1fr;gap:18px;background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:20px}
.spine{width:72px;height:96px;border-radius:4px 8px 8px 4px;background:#172029;color:#f07a3e;display:grid;place-items:center;font:700 1.4rem var(--serif);
box-shadow:inset 6px 0 0 rgba(255,255,255,.08),var(--shadow)}
.spine.alt{background:#1f5fa8;color:#fff}
.book h3{font-family:var(--sans);font-size:1.05rem;font-weight:600}
.book p{margin:4px 0 0;color:var(--ink-2);font-size:.9rem}
.book .status{font-family:var(--mono);font-size:.74rem;color:var(--ink-3);margin-top:8px}
.series{display:grid;gap:10px}
.series a{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:14px 18px;border-radius:12px;border:1px solid var(--rule);background:var(--card);text-decoration:none}
.series a:hover{border-color:var(--ink-3)}
.series span{color:var(--ink-3);font-family:var(--mono);font-size:.78rem;white-space:nowrap}
/* lesson article */
.lesson-layout{display:grid;gap:24px;padding-bottom:72px}
@media (min-width:1000px){.lesson-layout{grid-template-columns:230px minmax(0,1fr);gap:48px}}
.lesson-side{min-width:0}
@media (min-width:1000px){.lesson-side{position:sticky;top:84px;align-self:start;max-height:calc(100vh - 100px);overflow:auto}}
.toc details{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:12px 16px}
.toc summary{font-family:var(--mono);font-size:.78rem;color:var(--ink-3);cursor:pointer}
.toc ol{margin:10px 0 0;padding-left:20px;font-size:.9rem;display:grid;gap:6px}
.toc a{text-decoration:none;color:var(--ink-2)}
.toc a:hover{color:var(--accent)}
.lesson{min-width:0;max-width:760px}
.lesson-meta{display:flex;flex-wrap:wrap;gap:6px 16px;margin-top:16px;color:var(--ink-3);font-size:.86rem}
.lesson h2{font-size:clamp(1.4rem,3vw,1.8rem);margin:56px 0 14px;padding-top:8px}
.lesson h3{font-family:var(--sans);font-size:1.1rem;font-weight:600;margin:28px 0 8px}
.lesson p,.lesson li{color:var(--ink)}
.lesson p{margin:0 0 14px}
.lesson ul,.lesson ol{padding-left:22px;margin:0 0 14px}
.lesson li{margin-bottom:6px}
.lesson strong{font-weight:600}
.tldr{border:1px solid var(--rule);border-left:4px solid var(--accent);background:var(--card);border-radius:12px;padding:16px 20px;margin:28px 0 0}
.tldr b{font-family:var(--mono);font-size:.78rem;color:var(--accent);font-weight:500}
.tldr ul{margin:8px 0 0}
.tldr li{margin-bottom:4px}
.katex-display{overflow-x:auto;overflow-y:hidden;padding:6px 0;margin:14px 0!important}
.katex{font-size:1.08em}
.formula{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:6px 16px;margin:16px 0}
.formula .katex-display{margin:8px 0!important}
.formula figcaption{font-size:.84rem;color:var(--ink-3);padding:0 0 8px}
.example{border:1.5px solid var(--ink);border-radius:12px;background:var(--card);padding:18px 20px;margin:20px 0}
.example > .mono{color:var(--accent)}
.example h3{margin:4px 0 10px}
.example details{margin-top:10px;border-top:1px dashed var(--rule);padding-top:10px}
.example summary{cursor:pointer;color:var(--signal);font-weight:600;font-size:.95rem}
.example details[open] summary{margin-bottom:10px}
.answer{background:color-mix(in srgb,var(--ok) 12%,transparent);border-radius:8px;padding:10px 14px;margin-top:10px}
.note{border-radius:12px;background:color-mix(in srgb,var(--signal) 10%,transparent);border:1px solid color-mix(in srgb,var(--signal) 30%,transparent);padding:14px 18px;margin:18px 0;font-size:.95rem}
.note b{color:var(--signal)}
.table-wrap{overflow-x:auto;margin:16px 0;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.table-wrap table{border-collapse:collapse;width:100%;font-size:.95rem}
.table-wrap th,.table-wrap td{padding:10px 14px;border-bottom:1px solid var(--rule);text-align:left;vertical-align:middle}
.table-wrap th{font-family:var(--mono);font-size:.76rem;font-weight:500;color:var(--ink-3);background:var(--paper-2)}
.table-wrap tr:last-child td{border-bottom:0}
.flow{display:grid;gap:10px;margin:18px 0}
@media (min-width:640px){.flow{grid-template-columns:1fr auto 1fr auto 1fr;align-items:center}}
.flow div{background:var(--card);border:1.5px solid var(--ink);border-radius:10px;padding:12px 14px;text-align:center;font-size:.92rem}
.flow div b{display:block;font-family:var(--mono);font-size:.74rem;color:var(--accent);font-weight:500}
.flow i{font-style:normal;text-align:center;color:var(--ink-3)}
.circuit{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:16px;margin:16px 0;color:var(--ink)}
.circuit svg{width:100%;max-width:520px;margin:0 auto;height:auto}
.circuit figcaption{font-size:.84rem;color:var(--ink-3);text-align:center;margin-top:8px}
.lesson-video{margin-top:8px}
.faq details{border-bottom:1px solid var(--rule);padding:14px 0}
.faq summary{cursor:pointer;font-weight:600}
.faq details p{margin:10px 0 0;color:var(--ink-2)}
.pager{display:grid;gap:12px;margin-top:48px}
@media (min-width:640px){.pager{grid-template-columns:1fr 1fr}}
.pager a{display:flex;flex-direction:column;gap:2px;padding:16px 18px;border:1px solid var(--rule);border-radius:12px;background:var(--card);text-decoration:none}
.pager a:hover{border-color:var(--accent)}
.pager .mono{color:var(--ink-3)}
.pager-next{text-align:right}
.author{display:flex;gap:14px;align-items:center;margin-top:32px;padding:16px 18px;border:1px solid var(--rule);border-radius:12px;background:var(--paper-2)}
.author .avatar{width:52px;height:52px;border-radius:12px;flex:none;box-shadow:none}
.author .avatar span{font-size:1.1rem}
.author .avatar::after{display:none}
.author p{margin:0;font-size:.9rem;color:var(--ink-2)}
.author a{color:var(--signal);text-decoration:none}
/* ==========================================================================
PRINT (profile → CV / PDF)
========================================================================== */
@media print{
:root{--paper:#fff;--paper-2:#fff;--card:#fff;--ink:#000;--ink-2:#222;--ink-3:#555;--rule:#ccc;--shadow:none}
body{background:#fff;font-size:11pt}
.nav,.site-footer,.no-print,.filters,.feed-more,.cta-row,.bio-tabs,.bio-actions,.skip{display:none!important}
section.block,.profile{padding:14pt 0!important}
.tile,.work,.biokit,.now-list li{box-shadow:none;break-inside:avoid}
.bio-panel[hidden]{display:block!important}
.avatar::after{display:none}
a{text-decoration:none}
}
/* lesson TOC placement: sidebar on desktop, inline on mobile */
.lesson-side{display:none}
.toc-inline{margin-top:20px}
@media (min-width:1000px){.lesson-side{display:block}.toc-inline{display:none}}
.lesson-wrap{padding-top:36px}
@media print{.lesson-side,.toc-inline,.lesson-video,.pager{display:none!important}}
/* circuit diagrams */
.circuit .w{fill:none;stroke:currentColor;stroke-width:2;stroke-linejoin:round;stroke-linecap:round}
.circuit .m{fill:none;stroke:var(--accent);stroke-width:1.6}
.circuit .mt{fill:var(--accent)}
.circuit text{fill:currentColor;font-family:var(--mono);font-size:13px}
.circuit text.mt{fill:var(--accent);font-weight:500}
/* math on small screens: smaller display math, scroll cue when an equation is still wider than the screen */
@media (max-width:640px){
.katex-display > .katex{font-size:.9em}
.example{padding:16px 14px}
.formula{padding:4px 10px}
.katex-display{
background:
linear-gradient(90deg,var(--card) 30%,transparent) left/24px 100% no-repeat local,
linear-gradient(270deg,var(--card) 30%,transparent) right/24px 100% no-repeat local,
radial-gradient(farthest-side at 0 50%,rgba(0,0,0,.18),transparent) left/10px 100% no-repeat scroll,
radial-gradient(farthest-side at 100% 50%,rgba(0,0,0,.18),transparent) right/10px 100% no-repeat scroll;
}
}
/* ==========================================================================
TOOLS — lesson editor
========================================================================== */
.app-wrap{max-width:1440px}
.app-head{padding:28px 0 18px}
.app-head h1{font-size:clamp(1.6rem,3.6vw,2.4rem)}
.app-head .lede{margin:10px 0 0;font-size:1rem}
.app-title{display:grid;gap:18px}
@media (min-width:1000px){.app-title{grid-template-columns:1fr 420px;align-items:start}}
.cheat{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:12px 16px}
.cheat summary{cursor:pointer;font-weight:600;font-size:.95rem}
.cheat .table-wrap{margin:12px 0 8px}
.cheat td,.cheat th{padding:7px 10px;font-size:.88rem}
.cheat code{font-family:var(--mono);font-size:.8rem;background:var(--paper-2);padding:1px 6px;border-radius:5px;white-space:nowrap}
.cheat p{margin:6px 0 0;color:var(--ink-3)}
.editor-app{padding-bottom:40px}
.toolbar{display:flex;flex-wrap:wrap;gap:8px;align-items:center;padding:10px;border:1px solid var(--rule);border-radius:12px 12px 0 0;background:var(--paper-2)}
.toolbar label.btn{cursor:pointer}
.tb-gap{flex:1}
@media (max-width:640px){.tb-gap{display:none}.toolbar .btn{flex:1 1 auto;justify-content:center}}
.workspace{display:grid;grid-template-columns:1fr 1fr;gap:0;border:1px solid var(--rule);border-top:0;border-radius:0 0 12px 12px;overflow:hidden;background:var(--card);
height:max(520px,calc(100dvh - 190px))}
.pane{display:flex;flex-direction:column;min-width:0;min-height:0}
.pane + .pane{border-left:1px solid var(--rule)}
.panehead{display:flex;justify-content:space-between;align-items:center;padding:9px 16px;border-bottom:1px solid var(--rule);font-size:.9rem}
.panehead .mono{color:var(--ink-3)}
#source{flex:1;min-height:0;width:100%;border:0;resize:none;padding:18px 20px;font:14.5px/1.85 var(--mono);color:var(--ink);background:var(--card);outline:none;tab-size:2}
#source:focus-visible{box-shadow:inset 0 0 0 2px color-mix(in srgb,var(--accent) 40%,transparent)}
.preview{flex:1;min-height:0;overflow:auto;padding:24px 32px 40px;max-width:none}
.preview h1{font-size:clamp(1.5rem,3vw,2rem);margin:0 0 12px}
.preview h2{font-size:1.35rem;margin:36px 0 12px;padding-bottom:6px;border-bottom:1px solid var(--rule)}
.preview h3{margin:24px 0 8px}
.preview blockquote{border-left:4px solid var(--accent);background:var(--paper);margin:16px 0;padding:6px 16px;border-radius:0 8px 8px 0;color:var(--ink-2)}
.preview pre{overflow:auto;background:var(--paper-2);padding:12px;border-radius:8px}
.preview code{font-family:var(--mono);font-size:.88em}
.preview table{border-collapse:collapse;margin:14px 0}
.preview td,.preview th{border:1px solid var(--rule);padding:6px 10px}
.preview hr{border:0;border-top:1px solid var(--rule);margin:28px 0}
.preview img{max-width:100%;height:auto}
.app-status{margin:10px 2px 0;color:var(--ink-3)}
/* mobile preview mode */
.editor-app.is-mobile .workspace{grid-template-columns:1fr;background:var(--paper-2);padding:20px 0}
.editor-app.is-mobile #editorPane{display:none}
.editor-app.is-mobile .pane + .pane{border-left:0;width:100%;max-width:400px;margin:0 auto;background:var(--card);border:1px solid var(--rule);border-radius:22px;overflow:hidden;box-shadow:var(--shadow)}
.editor-app.is-mobile .preview{padding:18px}
/* small screens: stack editor over preview */
@media (max-width:820px){
.workspace{grid-template-columns:1fr;height:auto}
.pane + .pane{border-left:0;border-top:1px solid var(--rule)}
#source{flex:none;height:46vh;resize:vertical}
.preview{padding:18px 16px 28px;overflow:visible}
}
@media print{
body.editor-page .app-head,body.editor-page .toolbar,body.editor-page #editorPane,body.editor-page .panehead,
body.editor-page .app-status,body.editor-page .app-more{display:none!important}
body.editor-page .workspace{display:block;height:auto;border:0;overflow:visible;background:none}
body.editor-page .pane{display:block}
body.editor-page .preview{overflow:visible;padding:0}
body.editor-page .katex-display{overflow:visible}
}
/* home: tool teaser */
.tool-card{display:grid;gap:24px;background:var(--card);border:1px solid var(--rule);border-radius:16px;padding:24px;box-shadow:var(--shadow);align-items:center}
@media (min-width:860px){.tool-card{grid-template-columns:1.1fr 1fr;padding:32px}}
.tool-card h2{margin:0 0 10px}
.tool-card ul{margin:14px 0 20px;padding-left:20px;color:var(--ink-2)}
.mock{border:1px solid var(--rule);border-radius:12px;overflow:hidden;font-family:var(--mono);font-size:.8rem;background:var(--paper)}
.mock-bar{display:flex;gap:6px;padding:8px 10px;border-bottom:1px solid var(--rule);background:var(--paper-2)}
.mock-bar i{width:9px;height:9px;border-radius:50%;background:var(--rule)}
.mock-body{display:grid;grid-template-columns:1fr 1fr}
.mock-body pre{margin:0;padding:14px;white-space:pre-wrap;color:var(--ink-2);border-right:1px solid var(--rule);font:inherit;line-height:1.7}
.mock-body div{padding:14px;font-family:var(--sans);font-size:.92rem;background:var(--card)}
.mock-body div b{display:block;font-family:var(--serif);font-size:1.05rem;margin-bottom:6px}
/* ==========================================================================
LAB — first-order system
========================================================================== */
.fos-lab,.trig-lab,.int-page{
--s-cur:#eb6834; --s-p1:#2a78d6; --s-p2:#1baf7a; --helper:var(--ink-3); --hl:#1f5fa8;
padding-bottom:56px;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) :is(.fos-lab,.trig-lab,.int-page){--s-cur:#d95926;--s-p1:#3987e5;--s-p2:#199e70;--hl:#6aa6e8}}
:root[data-theme="dark"] :is(.fos-lab,.trig-lab,.int-page){--s-cur:#d95926;--s-p1:#3987e5;--s-p2:#199e70;--hl:#6aa6e8}
.lab-grid{display:grid;gap:20px}
@media (min-width:1100px){.lab-grid{grid-template-columns:300px minmax(0,1fr);gap:28px;align-items:start}}
.lab-panel{background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:6px 18px 16px}
@media (min-width:1100px){.lab-panel{position:sticky;top:76px;max-height:calc(100vh - 92px);overflow:auto}}
.ctl{padding:14px 0;border-bottom:1px solid var(--rule)}
.ctl:last-child{border-bottom:0}
.ctl-h{font:600 .78rem var(--mono);letter-spacing:.04em;color:var(--ink-3);margin:0 0 10px;text-transform:none}
.seg{display:flex;flex-wrap:wrap;gap:4px;background:var(--paper-2);border-radius:10px;padding:4px}
.seg button{flex:1 1 auto;font:500 .86rem var(--sans);padding:7px 10px;border:0;border-radius:7px;background:transparent;color:var(--ink-2);cursor:pointer;white-space:nowrap}
.seg button[aria-pressed="true"]{background:var(--card);color:var(--ink);box-shadow:var(--shadow);font-weight:600}
.seg-sm button{font-size:.82rem;padding:6px 8px}
.row{display:grid;gap:4px;margin-top:12px}
.row label{display:flex;justify-content:space-between;gap:8px;font-size:.9rem;color:var(--ink-2)}
.row output{font-family:var(--mono);font-size:.82rem;color:var(--ink)}
.row input[type=range]{width:100%;accent-color:var(--accent)}
.row.inline{grid-template-columns:auto 90px auto;align-items:center}
.rng{display:grid;grid-template-columns:1fr 84px;gap:8px;align-items:center}
.num{width:100%;font:500 .88rem var(--mono);padding:6px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink)}
.tau-read{margin:12px 0 0;padding:8px 12px;border-radius:8px;background:color-mix(in srgb,var(--accent) 12%,transparent);color:var(--ink);font-size:.9rem}
.checks{display:grid;gap:6px}
.checks label{display:flex;gap:8px;align-items:center;font-size:.9rem;color:var(--ink-2);cursor:pointer}
.checks input{accent-color:var(--accent);width:16px;height:16px}
.hint{margin:10px 0 0;font-size:.8rem;color:var(--ink-3);line-height:1.6}
.pins{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.pin{display:inline-flex;align-items:center;gap:6px;font:500 .8rem var(--mono);padding:4px 4px 4px 10px;border:1px solid var(--rule);border-radius:999px;background:var(--paper)}
.pin-x{border:0;background:transparent;color:var(--ink-3);cursor:pointer;font-size:1rem;line-height:1;padding:2px 6px;border-radius:50%}
.pin-x:hover{background:var(--paper-2);color:var(--ink)}
.ctl-actions{display:flex;flex-wrap:wrap;gap:8px}
.key{display:inline-block;width:16px;height:0;border-top:2.5px solid currentColor;vertical-align:middle;border-radius:2px}
.key.s-cur{color:var(--s-cur)} .key.s-p1{color:var(--s-p1)} .key.s-p2{color:var(--s-p2)}
.lab-main{display:grid;gap:16px;min-width:0}
.eqbar{display:grid;gap:10px;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:12px 16px}
.eqbar > div{min-width:0;overflow-x:auto}
.eqbar .mono{display:block;color:var(--ink-3);font-size:.72rem}
.eqbar .eq-wide{grid-column:1/-1}
@media (min-width:1300px){.eqbar .eq-wide{grid-column:auto / span 2}}
.eqbar .katex{font-size:1.05em}
.vcard{background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:14px 16px;min-width:0}
.vhead{display:flex;justify-content:space-between;gap:12px;align-items:flex-start;margin-bottom:6px}
.vhead h3{font-family:var(--sans);font-size:1rem;font-weight:600;margin:0}
.vhead p{margin:2px 0 0;font-size:.84rem;color:var(--ink-3)}
.legend{display:flex;flex-wrap:wrap;gap:4px 14px;margin-top:4px;font-size:.84rem;color:var(--ink-2)}
.legend .lg{display:inline-flex;align-items:center;gap:6px}
.vnote{margin:6px 0 0;font-size:.82rem;color:var(--ink-3)}
.vgrid{display:grid;gap:16px}
@media (min-width:900px){.vgrid{grid-template-columns:1fr 1fr}}
.chart{position:relative;min-width:0}
.plot{position:relative;width:100%}
.plot svg{display:block;max-width:100%;touch-action:pan-y;outline:none;border-radius:8px}
.plot svg:focus-visible{box-shadow:0 0 0 2px var(--accent)}
.plot .grid{stroke:var(--rule);stroke-width:1}
.plot .axis{stroke:var(--ink-3);stroke-width:1}
.plot .axis0{stroke:var(--ink-3);stroke-width:1;stroke-dasharray:2 3}
.plot .tick{fill:var(--ink-3);font:11px var(--mono)}
.plot .atitle{fill:var(--ink-3);font:500 11px var(--mono)}
.plot .lab{fill:var(--ink-2);font:500 11.5px var(--sans);paint-order:stroke;stroke:var(--card);stroke-width:4px;stroke-linejoin:round}
.plot .lab.muted{fill:var(--ink-3)}
.plot .lab.acc{fill:var(--hl)}
.plot .lab.tauk{fill:var(--ink-2);font:600 11px var(--mono)}
.plot .ser{fill:none;stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.plot .ser.s-cur{stroke:var(--s-cur);stroke-width:2.8}
.plot .ser.s-p1{stroke:var(--s-p1)}
.plot .ser.s-p2{stroke:var(--s-p2)}
.plot .h-input{fill:none;stroke:var(--ink-3);stroke-width:1.5;stroke-dasharray:6 4}
.plot .h-final{fill:none;stroke:var(--ink-2);stroke-width:1.3;stroke-dasharray:8 5}
.plot .h-guide{fill:none;stroke:var(--ink-3);stroke-width:1;stroke-dasharray:2 4}
.plot .h-tan{fill:none;stroke:var(--hl);stroke-width:1.5;stroke-dasharray:5 4}
.plot .h-tau{stroke:var(--ink-3);stroke-width:1;stroke-dasharray:1 4}
.plot .h-tau.one{stroke:var(--hl);stroke-dasharray:3 3}
.plot .h-mark{stroke:var(--hl);stroke-width:1;stroke-dasharray:2 3}
.plot .h-lag{stroke:var(--hl);stroke-width:1.3}
.plot .h-ek{stroke:var(--rule);stroke-width:1;stroke-dasharray:4 4}
.plot .h-band{fill:color-mix(in srgb,var(--hl) 12%,transparent)}
.plot .lhp{fill:color-mix(in srgb,var(--ok) 7%,transparent)}
.plot .ah{fill:var(--hl)}
.plot .h-input ~ .ah{fill:var(--ink-3)}
.plot .pt-tau{fill:var(--s-cur);stroke:var(--card);stroke-width:2}
.plot .pt-tan,.plot .pt-h{fill:var(--card);stroke:var(--hl);stroke-width:2}
.plot .pt-in{fill:var(--card);stroke:var(--ink);stroke-width:2}
.plot .pt-cur{stroke:var(--card);stroke-width:2.5}
.plot .pt-cur.s-cur{fill:var(--s-cur)} .plot .pt-cur.s-p1{fill:var(--s-p1)} .plot .pt-cur.s-p2{fill:var(--s-p2)}
.plot .pole{fill:none;stroke-width:2.8;stroke-linecap:round}
.plot .pole.s-cur{stroke:var(--s-cur)} .plot .pole.s-p1{stroke:var(--s-p1)} .plot .pole.s-p2{stroke:var(--s-p2)}
.plot .hair{stroke:var(--ink-2);stroke-width:1}
.plot-tip{position:absolute;z-index:2;min-width:170px;pointer-events:none;background:var(--card);border:1px solid var(--rule);border-radius:10px;box-shadow:var(--shadow);padding:8px 12px;font-size:.84rem}
.tt-head{font-family:var(--mono);font-size:.78rem;color:var(--ink-3);margin-bottom:4px}
.tt-head b{color:var(--ink);font-size:.86rem}
.tt-row{display:flex;align-items:center;gap:6px;white-space:nowrap}
.tt-row b{font-family:var(--mono);font-weight:600}
.tt-row span{color:var(--ink-3)}
.tt-row.sub{font-size:.78rem}
.tt-row.sub:first-of-type{margin-top:4px}
.miles{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:8px}
.mile{display:flex;flex-direction:column;gap:1px;padding:10px 12px;border-radius:12px;border:1px solid var(--rule);background:var(--card);transition:background .2s,border-color .2s,transform .2s}
.mile-k{color:var(--accent);font-size:.78rem}
.mile-p{font:700 1.15rem var(--serif)}
.mile-t,.mile-y{font-size:.78rem;color:var(--ink-2)}
.mile.passed{border-color:var(--s-cur);background:color-mix(in srgb,var(--s-cur) 12%,var(--card))}
@media (max-width:600px){.miles{grid-template-columns:repeat(3,minmax(0,1fr))}.mile-p{font-size:1rem}}
.miles-note{margin:-6px 2px 0;color:var(--ink-3);font-size:.74rem}
.stats{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:8px}
.stat{display:flex;flex-direction:column;padding:10px 12px;border-radius:12px;border:1px solid var(--rule);background:var(--card)}
.stat-l{font-size:.78rem;color:var(--ink-3)}
.stat-v{font:600 1rem var(--mono);margin-top:2px}
.stat-n{font-size:.74rem;color:var(--ink-3)}
.table-view summary{cursor:pointer;font-weight:600}
.table-view .table-wrap{margin:12px 0 0}
.table-view td{font-family:var(--mono);font-size:.86rem}
@media print{.fos-lab{display:none}}
/* home: lab teaser */
.lab-teaser{display:grid;gap:24px;align-items:center}
@media (min-width:860px){.lab-teaser{grid-template-columns:1fr 1.1fr}}
.lab-teaser svg{width:100%;height:auto;background:var(--card);border:1px solid var(--rule);border-radius:14px;box-shadow:var(--shadow)}
.lab-teaser .t-curve{fill:none;stroke:var(--accent);stroke-width:3;stroke-linecap:round}
.lab-teaser .t-grid{stroke:var(--rule);stroke-width:1}
.lab-teaser .t-tau{stroke:var(--ink-3);stroke-width:1;stroke-dasharray:2 4}
.lab-teaser .t-tan{stroke:var(--signal);stroke-width:1.5;stroke-dasharray:5 4}
.lab-teaser .t-final{stroke:var(--ink-2);stroke-width:1.2;stroke-dasharray:8 5}
.lab-teaser .t-dot{fill:var(--accent);stroke:var(--card);stroke-width:2}
.lab-teaser text{font:500 12px var(--mono);fill:var(--ink-2)}
.lab-teaser text.acc{fill:var(--signal)}
@media (min-width:1900px){.nav-links .nav-home{display:none}}
@media (min-width:1000px){.topic-grid{grid-template-columns:repeat(auto-fit,minmax(190px,1fr))}}
/* lab on narrow screens: chart first, then controls, then the other views */
@media (max-width:1099px){
.lab-main{display:contents}
.lab-grid .eqbar{order:1}
.lab-grid .vmain{order:2}
.lab-grid .lab-panel{order:3}
.lab-grid .miles,.lab-grid .miles-note{order:4}
.lab-grid .stats{order:5}
.lab-grid .vgrid{order:6}
.lab-grid .table-view{order:7}
.lab-grid{gap:14px}
}
/* ==========================================================================
LAB — second-order system (shares .fos-lab styles)
========================================================================== */
.ctl-key{background:color-mix(in srgb,var(--accent) 6%,transparent);margin:0 -18px;padding:14px 18px}
.presets{display:grid;grid-template-columns:repeat(3,1fr);gap:6px;margin-bottom:6px}
.presets button{display:flex;flex-direction:column;align-items:center;gap:0;padding:7px 4px;border:1px solid var(--rule);border-radius:9px;background:var(--card);color:var(--ink);font:600 .95rem var(--mono);cursor:pointer;line-height:1.25}
.presets button small{font:400 .68rem var(--sans);color:var(--ink-3)}
.presets button[aria-pressed="true"]{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 14%,var(--card))}
.presets button:hover{border-color:var(--ink-3)}
.row input:disabled{opacity:.45}
.regime{margin:6px 0 0;font-size:.84rem}
.regime #regime2{display:inline-block;padding:2px 10px;border-radius:999px;font-weight:600;background:var(--paper-2);border:1px solid var(--rule)}
.regime #regime2[data-k="under"]{border-color:var(--s-cur);color:var(--ink)}
.regime #regime2[data-k="crit"]{border-color:var(--s-p2)}
.regime #regime2[data-k="over"]{border-color:var(--s-p1)}
.regime #regime2[data-k="none"]{border-style:dashed}
.regime .muted{color:var(--ink-3)}
.vbtns{display:flex;flex-wrap:wrap;gap:6px;justify-content:flex-end}
.span-all{grid-column:1/-1}
.plot .fam{fill:none;stroke:var(--ink-3);stroke-width:1;opacity:.55}
.plot .lab.fam-l{fill:var(--ink-3);font-size:10.5px}
.key.fam-k{color:var(--ink-3);border-top-style:solid;opacity:.7}
.plot .ser.thin{stroke-width:1.6}
.plot .ser.s-neutral{stroke:var(--ink-2);stroke-width:2.2}
.plot .h-env{fill:none;stroke:var(--hl);stroke-width:1.4;stroke-dasharray:6 4}
.plot .h-env2{fill:none;stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:2 4}
.plot .h-peak{stroke:var(--hl);stroke-width:1.3}
.plot .pt-peak{fill:var(--hl);stroke:var(--card);stroke-width:2}
.plot .pt-pk{fill:var(--card);stroke:var(--s-cur);stroke-width:2}
.plot .pt-tr{fill:var(--card);stroke:var(--ink-3);stroke-width:1.6}
.plot .locus{fill:none;stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:4 4}
.plot .h-geo{stroke:var(--hl);stroke-width:1.4}
.plot .h-proj{stroke:var(--ink-3);stroke-width:1;stroke-dasharray:3 3}
.plot .h-arc{fill:none;stroke:var(--hl);stroke-width:1.4}
.plot .drag{fill:color-mix(in srgb,var(--s-cur) 14%,transparent);stroke:var(--s-cur);stroke-width:1;stroke-dasharray:3 3;cursor:grab}
#chartS2 svg{cursor:crosshair;touch-action:none}
.lab-cards{display:grid;gap:16px}
@media (min-width:860px){.lab-cards{grid-template-columns:1fr 1fr}}
.lab-card{display:flex;flex-direction:column;gap:6px;text-decoration:none;background:var(--card);border:1px solid var(--rule);border-radius:16px;padding:18px;box-shadow:var(--shadow);transition:transform .18s,border-color .18s}
.lab-card:hover{transform:translateY(-3px);border-color:var(--accent)}
.lab-card svg{width:100%;height:auto;border-radius:10px;background:var(--paper);border:1px solid var(--rule);margin-bottom:8px}
.lab-card .mono{color:var(--accent)}
.lab-card b{font:700 1.2rem/1.35 var(--serif)}
.lab-card > span:not(.mono):not(.tc-go){color:var(--ink-2);font-size:.93rem}
.lab-card .tc-go{margin-top:auto;padding-top:8px;font:500 .82rem var(--mono);color:var(--signal)}
.lab-card .t-curve{fill:none;stroke:var(--accent);stroke-width:3;stroke-linecap:round}
.lab-card .t-grid{stroke:var(--rule);stroke-width:1}
.lab-card .t-tau{stroke:var(--ink-3);stroke-width:1;stroke-dasharray:2 4}
.lab-card .t-tan{stroke:var(--signal);stroke-width:1.5;stroke-dasharray:5 4}
.lab-card .t-final{stroke:var(--ink-2);stroke-width:1.2;stroke-dasharray:8 5}
.lab-card .t-dot{fill:var(--accent);stroke:var(--card);stroke-width:2}
.lab-card text{font:500 12px var(--mono);fill:var(--ink-2)}
.lab-card text.acc{fill:var(--signal)}
@media (min-width:1000px){.topic-grid{grid-template-columns:repeat(3,1fr)}}
/* ==========================================================================
LAB — signals
========================================================================== */
.sig-top{display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;align-items:center;margin-bottom:16px}
.seg-lg button{font-size:.95rem;padding:9px 14px}
.sig-lab{--s-neu:var(--ink-3)}
.expr-l{display:block;font:600 .9rem var(--mono);color:var(--ink-2);margin-bottom:4px}
.expr{width:100%;font:500 .95rem var(--mono);padding:9px 10px;border:1.5px solid var(--rule);border-radius:9px;background:var(--paper);color:var(--ink)}
.expr:focus{outline:none;border-color:var(--accent)}
.expr.bad{border-color:#d14343}
.expr-err{min-height:0;margin:4px 0 0;font-size:.8rem;color:#c43c3c}
.expr-err:empty{display:none}
.pre{width:100%;margin-top:8px;font:500 .86rem var(--sans);padding:7px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--card);color:var(--ink)}
.fnbar{display:flex;flex-wrap:wrap;gap:4px;margin-top:8px}
.fnbar button{font:500 .8rem var(--mono);padding:4px 9px;border-radius:7px;border:1px solid var(--rule);background:var(--card);color:var(--ink-2);cursor:pointer}
.fnbar button:hover{border-color:var(--accent);color:var(--ink)}
.fnhelp{margin-top:8px;font-size:.8rem;color:var(--ink-3)}
.fnhelp summary{cursor:pointer;color:var(--signal)}
.fnhelp p{margin:6px 0 0;line-height:1.7}
.win{grid-template-columns:1fr auto 1fr!important}
.win span{font-size:.85rem;color:var(--ink-3)}
.stage{font-size:.78rem;color:var(--accent);align-self:center}
.vgrid.three{grid-template-columns:1fr}
@media (min-width:900px){.vgrid.three{grid-template-columns:repeat(3,1fr)}}
.plot .ser.s-neu{stroke:var(--ink-3)}
.plot .ser.dash{stroke-dasharray:6 4;stroke-width:1.6}
.plot .ser.faint{opacity:.35;stroke-width:1.6}
.key.s-neu{color:var(--ink-3)}
.key.s-neu.dash{border-top-style:dashed}
.plot .stem{stroke-width:1.6}
.plot .stem.s-cur{stroke:var(--s-cur)} .plot .stem.s-p1{stroke:var(--s-p1)} .plot .stem.s-p2{stroke:var(--s-p2)} .plot .stem.s-neu{stroke:var(--ink-3)}
.plot .stem-dot{stroke:var(--card);stroke-width:1.5}
.plot .stem-dot.s-cur{fill:var(--s-cur)} .plot .stem-dot.s-p1{fill:var(--s-p1)} .plot .stem-dot.s-p2{fill:var(--s-p2)} .plot .stem-dot.s-neu{fill:var(--ink-3)}
.plot .stem.faint,.plot .stem-dot.faint{opacity:.35}
.plot .impl{stroke-width:2.2}
.plot .impl.s-cur{stroke:var(--s-cur)} .plot .impl.s-p1{stroke:var(--s-p1)} .plot .impl.s-p2{stroke:var(--s-p2)} .plot .impl.s-neu{stroke:var(--ink-3)}
.plot .impl.faint{opacity:.35}
.plot .im.s-cur{fill:var(--s-cur)} .plot .im.s-p1{fill:var(--s-p1)} .plot .im.s-p2{fill:var(--s-p2)} .plot .im.s-neu{fill:var(--ink-3)}
.plot .lab.imp-l{font:500 10.5px var(--mono);fill:var(--ink-2)}
.plot .jd{stroke:var(--card);stroke-width:1.5}
.plot .jd.s-cur{fill:var(--s-cur)} .plot .jd.s-p1{fill:var(--s-p1)} .plot .jd.s-p2{fill:var(--s-p2)}
.plot .jd.open{fill:var(--card);stroke:var(--ink-2);stroke-width:1.6}
.plot .samp-l{stroke:var(--hl);stroke-width:1.3}
.plot .samp-d{fill:var(--hl);stroke:var(--card);stroke-width:1.5}
.plot .pt-zero{fill:var(--card);stroke:var(--ink-2);stroke-width:1.5}
.plot .pt-map0{fill:var(--hl);stroke:var(--card);stroke-width:2}
.plot .pt-map1{fill:var(--card);stroke:var(--hl);stroke-width:2.2}
.plot .maparrow{fill:none;stroke:var(--hl);stroke-width:1.4;stroke-dasharray:4 3}
.plot .conv-area{fill:color-mix(in srgb,var(--s-cur) 28%,transparent);stroke:none}
.plot .igrid{stroke:var(--rule);stroke-width:1;stroke-dasharray:1 3}
.plot .axis0.v{stroke-dasharray:2 3}
.lab-card .t-area{fill:color-mix(in srgb,var(--accent) 25%,transparent)}
@media (min-width:1100px){.lab-cards{grid-template-columns:repeat(3,1fr)}}
@media (max-width:1099px){.lab-grid #sgConvCard{order:2}}
/* ==========================================================================
TRIGONOMETRY — formulas, unit circle, 0–90° table
========================================================================== */
.trig-lab{padding-bottom:0}
.trig-quick{display:flex;flex-wrap:wrap;gap:8px;margin-top:18px}
.tf-filter{display:flex;flex-wrap:wrap;align-items:center;gap:8px 12px;margin:28px 0 0;padding:12px 14px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.tf-filter label{font-weight:600;font-size:.92rem}
.tf-filter input{flex:1 1 240px;min-width:0;font:inherit;font-size:.95rem;padding:8px 12px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.tf-count{color:var(--ink-3)}
.tf-grid{display:grid;gap:12px;margin:16px 0}
.tf-grid{grid-template-columns:repeat(auto-fill,minmax(min(100%,360px),1fr))}
.tf-grid .tf.wide{grid-column:1/-1}
@media (max-width:380px){.tf .katex-display > .katex{font-size:.84em}}
.tf{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:12px 16px 6px;min-width:0}
.tsec > .tf{margin:16px 0}
.lesson .tf-n{margin:0 0 2px;font-size:.9rem;color:var(--ink-2)}
.tf-n b{display:block;font-family:var(--mono);font-size:.78rem;font-weight:500;color:var(--accent);letter-spacing:.01em}
.tf .katex-display{margin:6px 0!important}
.lesson .tf-x{font-size:.86rem;color:var(--ink-3);margin:0 0 10px}
.is-filtering .tsec:not(.tsec-all) > :not(h2):not(.tf-grid):not(.tf){display:none}
.is-filtering .tsec h2{margin-top:32px}
.tf-off{display:none}
.astc{display:grid;grid-template-columns:1fr 1fr;gap:6px;margin:8px 0}
.astc div{border:1px solid var(--rule);border-radius:8px;padding:6px 10px;font-size:.84rem;background:var(--paper)}
.astc b{display:block;font-family:var(--mono);font-size:.76rem;color:var(--accent);font-weight:500}
.table-wrap table.exact td{white-space:nowrap}
.table-wrap tr.hl td{background:color-mix(in srgb,var(--accent) 8%,transparent)}
/* unit circle */
.trig-lab{margin:20px 0 8px;display:grid;gap:12px;overflow-anchor:none}
.uc-grid{display:grid;gap:16px;background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:14px}
@media (min-width:700px){.uc-grid{grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);align-items:start}}
.uc-fig svg{width:100%;height:auto;touch-action:pan-y;user-select:none;-webkit-user-select:none;border-radius:10px;background:var(--paper);outline:none}
.uc-fig svg:focus-visible{box-shadow:0 0 0 2px var(--accent)}
.lesson .uc-hint{margin:6px 0 0;font-size:.8rem;color:var(--ink-3);text-align:center}
.uc-theta{display:flex;flex-wrap:wrap;align-items:baseline;gap:2px 10px}
.uc-theta .mono{width:100%;color:var(--ink-3)}
.uc-theta b{font:700 2rem/1.15 var(--serif)}
.uc-rad{font-family:var(--mono);font-size:.84rem;color:var(--ink-2);min-height:2.6em;display:flex;align-items:center;gap:4px;flex-wrap:wrap}
.uc-rad .katex{font-size:1em}
.rng.uc-num{grid-template-columns:minmax(0,1fr) auto;margin-top:10px}
.num.bad{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 8%,var(--paper))}
.uc-presets{display:flex;flex-wrap:wrap;gap:4px;margin:10px 0 12px}
.uc-presets button{font:500 .78rem var(--mono);padding:5px 7px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink-2);cursor:pointer;min-width:44px}
.uc-presets button:hover{border-color:var(--ink-3);color:var(--ink)}
.uc-side .checks{margin-bottom:12px}
.uc-ax{stroke:var(--ink-3);stroke-width:1}
.uc-axl{fill:var(--ink-3);font:italic 14px var(--serif)}
.uc-tl{stroke:var(--rule);stroke-width:1.2;stroke-dasharray:4 4}
.uc-circle{fill:none;stroke:var(--ink-2);stroke-width:1.6}
.uc-ring{fill:none;stroke:transparent;stroke-width:40;cursor:grab;touch-action:none;pointer-events:stroke}
.uc-tick > circle:first-child{fill:var(--ink-3)}
.uc-tick text{fill:var(--ink-2);font:500 11.5px var(--mono);pointer-events:none;paint-order:stroke;stroke:var(--paper);stroke-width:3px;stroke-linejoin:round}
.uc-hitlab{fill:transparent;cursor:pointer}
.uc-tick.on text{opacity:0}
.uc-tick.on > circle:first-child{fill:var(--accent)}
.uc-q text{fill:var(--ink-3);font:500 11px var(--mono)}
.uc-q text.on{fill:var(--accent);font-weight:700}
.uc-seg{stroke-width:4;stroke-linecap:round}
.uc-seg.s-cur{stroke:var(--s-cur)} .uc-seg.s-p1{stroke:var(--s-p1)} .uc-seg.s-p2{stroke:var(--s-p2)}
.uc-seg.rec{stroke:var(--ink-2);stroke-width:3;stroke-dasharray:6 4;stroke-linecap:butt}
.uc-ext{stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:3 4}
.uc-ext.rec{stroke:var(--ink-2)}
.uc-help{stroke:var(--s-cur);stroke-width:1;stroke-dasharray:2 4;opacity:.75}
.uc-radius{stroke:var(--ink);stroke-width:2}
.uc-arc{fill:none;stroke:var(--hl);stroke-width:2}
.uc-refarc{fill:none;stroke:var(--hl);stroke-width:1.5;stroke-dasharray:4 3}
.uc-p{fill:var(--accent);stroke:var(--card);stroke-width:2.5;pointer-events:none}
.uc-phit{fill:transparent;cursor:grab;touch-action:none}
.uc-dot{stroke:var(--card);stroke-width:2;pointer-events:none}
.uc-dot.s-p2{fill:var(--s-p2)}
.uc-lab{font:600 13px var(--sans);fill:var(--ink-2);paint-order:stroke;stroke:var(--paper);stroke-width:4px;stroke-linejoin:round;pointer-events:none}
.uc-lab.s-cur{fill:color-mix(in srgb,var(--s-cur) 80%,var(--ink))}
.uc-lab.s-p1{fill:var(--s-p1)}
.uc-lab.s-p2{fill:color-mix(in srgb,var(--s-p2) 70%,var(--ink))}
.uc-lab.acc,.uc-lab.th{fill:var(--hl)}
.uc-lab.th{font:italic 700 14px var(--serif)}
.uc-lab.muted{fill:var(--ink-3)}
.uc-lab.pl{fill:var(--accent);font-weight:700}
.uc-info{display:flex;flex-wrap:wrap;gap:6px 16px;align-items:center;font-size:.9rem;color:var(--ink-2);padding:10px 14px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.uc-info .mono{color:var(--ink-3)}
.uc-vals{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}
@media (max-width:520px){.uc-vals{grid-template-columns:repeat(2,minmax(0,1fr))}}
.uv{display:flex;flex-direction:column;gap:2px;padding:9px 12px;border:1px solid var(--rule);border-top:3px solid var(--rule);border-radius:12px;background:var(--card);min-width:0}
.uv.s-cur{border-top-color:var(--s-cur)} .uv.s-p1{border-top-color:var(--s-p1)} .uv.s-p2{border-top-color:var(--s-p2)}
.uv-n{font:600 .9rem var(--sans);display:flex;justify-content:space-between;align-items:baseline;gap:6px}
.uv-n small{font:400 .7rem var(--mono);color:var(--ink-3)}
.uv b{font:600 1.02rem var(--mono)}
.uv-x{font-size:.82rem;color:var(--ink-3);min-height:1.6em;overflow-x:auto;overflow-y:hidden}
.uv-x .katex{font-size:1em}
.tt-go{font:600 .84rem var(--sans);color:var(--signal);background:transparent;border:1px solid color-mix(in srgb,var(--signal) 40%,transparent);border-radius:999px;padding:5px 12px;cursor:pointer}
.tt-go:hover{background:color-mix(in srgb,var(--signal) 10%,transparent)}
/* 0–90° table */
.tt-tools{display:grid;gap:12px;margin:18px 0 14px}
.tt-find{display:grid;gap:12px}
@media (min-width:700px){.tt-find{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}}
.tt-box{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:12px 14px;min-width:0}
.tt-l{display:block;font-weight:600;font-size:.95rem;margin-bottom:8px}
.tt-l span{display:block;font-weight:400;font-size:.8rem;color:var(--ink-3)}
.tt-in{display:flex;gap:8px;align-items:center}
.tt-in .num{flex:1;min-width:0;font-size:1rem;padding:8px 10px}
.tt-in .seg{flex:none}
.tt-out{font-size:.88rem;color:var(--ink-2)}
.tt-out:empty{display:none}
.lesson .tt-out p{margin:8px 0 0;color:var(--ink-2)}
.lesson .tt-out .tt-head{font-family:var(--mono);font-size:.84rem;color:var(--ink)}
.tt-head .katex{font-size:1em}
.tt-cells{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:6px;margin-top:8px}
.tt-cells div{display:flex;flex-direction:column;padding:6px 8px;border-radius:8px;background:var(--paper);min-width:0}
.tt-cells span{font-size:.76rem;color:var(--ink-3)}
.tt-cells b{font:600 .84rem var(--mono);overflow-wrap:anywhere}
@media (max-width:520px){.tt-cells b{font-size:.74rem}.tt-cells div{padding:6px}}
.tt-cells i{font-style:normal;font-size:.8rem;overflow-x:auto;overflow-y:hidden}
.lesson .tt-out .tt-err{color:var(--accent)}
.tt-out .tt-go{margin-top:10px}
.tt-jump{display:flex;flex-wrap:wrap;gap:4px;align-items:center}
.tt-jump .mono{color:var(--ink-3);margin-right:4px}
.tt-jump a{font:500 .8rem var(--mono);text-decoration:none;padding:4px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--card);color:var(--ink-2)}
.tt-jump a:hover{border-color:var(--accent);color:var(--accent)}
.tt-actions{display:flex;flex-wrap:wrap;gap:8px 14px;align-items:center}
.tt-actions .hint{margin:0}
.tt-wrap{border:1px solid var(--rule);border-radius:12px;background:var(--card)}
table.tt{width:100%;border-collapse:separate;border-spacing:0;font-family:var(--mono);font-size:.86rem;font-variant-numeric:tabular-nums}
table.tt caption{caption-side:top;text-align:left;padding:10px 14px;font-family:var(--sans);font-size:.84rem;color:var(--ink-3)}
table.tt thead th{position:sticky;top:62px;z-index:2;background:var(--paper-2);padding:8px 10px;text-align:right;font-size:.82rem;font-weight:600;color:var(--ink);border-block:1px solid var(--rule)}
table.tt thead th small{display:block;font-weight:400;font-size:.68rem;color:var(--ink-3)}
table.tt tbody th,table.tt td{padding:3px 10px;text-align:right;border-bottom:1px solid color-mix(in srgb,var(--rule) 45%,transparent);white-space:nowrap;font-weight:400}
table.tt tbody th{color:var(--ink-2);font-weight:500}
table.tt tbody:nth-of-type(even) :is(th,td){background:color-mix(in srgb,var(--paper-2) 60%,transparent)}
table.tt tbody tr:first-child :is(th,td){border-top:1px solid var(--rule)}
table.tt tbody tr:first-child th{color:var(--ink);font-weight:700}
table.tt td small{display:block;font-size:.7rem;color:var(--accent);line-height:1.15}
table.tt tr.sp :is(th,td){background:color-mix(in srgb,var(--accent) 10%,var(--card));font-weight:700;color:var(--ink)}
table.tt td.undef small{color:var(--ink-3)}
table.tt tr{scroll-margin-top:52px}
table.tt tbody :is(th,td):hover{background:color-mix(in srgb,var(--signal) 12%,var(--card));cursor:copy}
table.tt tr:target :is(th,td),table.tt tr.hit :is(th,td){background:color-mix(in srgb,var(--signal) 24%,var(--card));color:var(--ink)}
@media (max-width:520px){
table.tt{font-size:.74rem}
table.tt tbody th,table.tt td{padding:3px 5px}
table.tt thead th{padding:6px 5px;font-size:.74rem}
table.tt caption{padding:10px}
}
.tt-fab{position:fixed;right:16px;bottom:16px;z-index:20;padding:10px 16px;border-radius:999px;background:var(--ink);color:var(--paper);text-decoration:none;font:600 .9rem var(--sans);box-shadow:var(--shadow)}
.tt-toast{position:fixed;left:50%;bottom:72px;transform:translateX(-50%);z-index:40;background:var(--ink);color:var(--paper);padding:8px 16px;border-radius:10px;font-size:.88rem;box-shadow:var(--shadow);max-width:calc(100vw - 32px);text-align:center}
@media print{.trig-lab,.tf-filter,.tt-tools,.tt-fab,.trig-quick{display:none!important}table.tt thead th{position:static}}
/* home: trig reference teaser */
.ref-card{display:grid;gap:22px;align-items:center;background:var(--card);border:1px solid var(--rule);border-radius:18px;padding:22px;box-shadow:var(--shadow)}
@media (min-width:860px){.ref-card{grid-template-columns:260px 1fr;padding:28px 32px}}
.ref-card svg{width:100%;max-width:260px;height:auto;margin:0 auto}
.ref-card h2,.ref-card h3{margin:6px 0 10px}
.ref-card h3{font:700 clamp(1.3rem,2.6vw,1.6rem)/1.3 var(--serif)}
.ref-card p{margin:0 0 14px;color:var(--ink-2)}
.ref-chips{display:flex;flex-wrap:wrap;gap:6px;margin:0 0 16px}
.ref-chips a{font:500 .82rem var(--mono);text-decoration:none;padding:5px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink-2)}
.ref-chips a:hover{border-color:var(--accent);color:var(--accent)}
.ref-card .cta-row{display:flex;flex-wrap:wrap;gap:10px}
.ref-card .rc-c{fill:none;stroke:var(--ink-2);stroke-width:1.6}
.ref-card .rc-ax{stroke:var(--ink-3);stroke-width:1}
.ref-card .rc-r{stroke:var(--ink);stroke-width:2}
.ref-card .rc-cos{stroke:#2a78d6;stroke-width:4;stroke-linecap:round}
.ref-card .rc-sin{stroke:#eb6834;stroke-width:4;stroke-linecap:round}
.ref-card .rc-tan{stroke:#1baf7a;stroke-width:4;stroke-linecap:round}
.ref-card .rc-p{fill:var(--accent);stroke:var(--card);stroke-width:2.5}
.ref-card text{font:600 12px var(--sans);fill:var(--ink-2)}
/* share bar (lesson pages) */
.share{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-top:40px;padding:14px 16px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.share .mono{color:var(--ink-3);margin-right:4px}
.share a,.share button{font:600 .86rem var(--sans);padding:7px 14px;border-radius:999px;border:1px solid var(--rule);background:var(--paper);color:var(--ink);text-decoration:none;cursor:pointer}
.share a:hover,.share button:hover{border-color:var(--accent);color:var(--accent)}
.share + .pager{margin-top:16px}
@media print{.share{display:none!important}}
/* ==========================================================================
INTEGRAL CALCULUS — lecture-style worked solutions
========================================================================== */
.int-page{padding-bottom:0;--hl-f:#f2b705;--hl-p:#2a78d6;--hl-u:#1baf7a;--hl-c:#9b5de5;--red:#e0352b}
.int-legend{display:flex;flex-wrap:wrap;gap:6px 16px;align-items:center;margin-top:18px;padding:10px 14px;border:1px dashed var(--rule);border-radius:12px;font-size:.84rem;color:var(--ink-2)}
.int-legend .mono{color:var(--ink-3);margin-right:4px}
.int-legend span{display:inline-flex;align-items:center;gap:6px}
.int-legend i{display:inline-block;width:18px;height:12px;border-radius:3px}
.int-legend .lg-f{background:color-mix(in srgb,var(--hl-f) 35%,transparent)}
.int-legend .lg-p{background:color-mix(in srgb,var(--hl-p) 22%,transparent)}
.int-legend .lg-u{background:color-mix(in srgb,var(--hl-u) 24%,transparent);outline:1.5px solid var(--hl-u)}
.int-legend .lg-c{background:color-mix(in srgb,var(--hl-c) 24%,transparent)}
.int-legend .lg-x{background:linear-gradient(to top right,transparent 44%,var(--red) 46%,var(--red) 54%,transparent 56%)}
.katex .hl-f{background:color-mix(in srgb,var(--hl-f) 32%,transparent);border-radius:4px;padding:0 .1em}
.katex .hl-p{background:color-mix(in srgb,var(--hl-p) 18%,transparent);border-radius:4px;padding:0 .1em}
.katex .hl-u{background:color-mix(in srgb,var(--hl-u) 20%,transparent);box-shadow:inset 0 -2px 0 var(--hl-u);border-radius:4px;padding:0 .1em}
.katex .hl-c{background:color-mix(in srgb,var(--hl-c) 22%,transparent);border-radius:4px;padding:0 .1em}
.katex .rc svg{stroke:var(--red)!important}
.katex .rc svg line{stroke-width:2px!important}
.katex .carry{color:var(--red);font-weight:700}
.fid{display:inline-block;min-width:2.2em;margin-right:6px;padding:0 5px;border-radius:5px;background:var(--ink);color:var(--paper);font:600 .72rem/1.6 var(--mono);text-align:center}
.int-page .tf:target{outline:2px solid var(--accent);outline-offset:2px}
.tag{display:inline-block;margin:2px 2px 0 0;padding:1px 8px;border-radius:999px;font:600 .72rem/1.6 var(--mono);text-decoration:none;white-space:nowrap;vertical-align:1px}
.tag.tf{background:color-mix(in srgb,var(--hl-f) 30%,var(--card));color:var(--ink)}
.tag.tp{background:color-mix(in srgb,var(--hl-p) 16%,var(--card));color:var(--ink)}
.tag:hover{outline:1.5px solid var(--ink-3)}
.note.warn{background:color-mix(in srgb,var(--red) 8%,transparent);border-color:color-mix(in srgb,var(--red) 35%,transparent)}
.note.warn b{color:var(--red)}
.wx{border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:16px 20px 12px;margin:22px 0;scroll-margin-top:80px}
.wx-head{display:flex;flex-wrap:wrap;align-items:flex-start;justify-content:space-between;gap:6px 12px}
.wx-head .mono{width:100%;color:var(--accent)}
.lesson .wx-head h3{margin:2px 0 6px;flex:1 1 280px}
.wx-bar{display:flex;gap:6px}
.wx-btn{font:600 .8rem var(--sans);padding:6px 12px;border-radius:999px;border:1px solid var(--rule);background:var(--paper);color:var(--signal);cursor:pointer;white-space:nowrap}
.wx-btn:hover{border-color:var(--signal)}
.lesson .steps{list-style:none;counter-reset:st;padding:0;margin:10px 0 0;border-top:1px dashed var(--rule)}
.lesson .steps > li{counter-increment:st;position:relative;padding:12px 0 6px 42px;margin:0;border-bottom:1px dashed var(--rule)}
.lesson .steps > li::before{content:counter(st);position:absolute;left:0;top:13px;width:28px;height:28px;border-radius:50%;background:var(--ink);color:var(--paper);display:grid;place-items:center;font:600 .82rem var(--mono)}
.lesson .steps > li > p{margin:0 0 4px}
.lesson .steps .katex-display{margin:6px 0!important}
.steps > li.st-hide,.wx.st-pending .answer,.wx.st-pending .check{display:none}
.practice .wx:not(.open) .steps,.practice .wx:not(.open) .answer,.practice .wx:not(.open) .check{display:none}
.lesson .check{font-size:.88rem;color:var(--ink-2);margin:8px 0 0}
.wx .answer{margin-top:12px}
.usub-map{display:grid;gap:10px;margin:18px 0}
@media (min-width:760px){.usub-map{grid-template-columns:repeat(3,minmax(0,1fr))}}
.usub-map > div{border:1.5px solid var(--hl-u);border-radius:12px;background:color-mix(in srgb,var(--hl-u) 6%,var(--card));padding:12px 14px;text-align:center;min-width:0;overflow-x:auto}
.usub-map .mono{display:block;color:var(--ink-3);margin-bottom:4px}
.lesson .usub-map p{margin:6px 0 0;font-size:.84rem;color:var(--ink-2);text-align:left}
.lesson ol.strategy{padding-left:24px}
.strategy li{margin-bottom:8px}
.strategy b{color:var(--accent)}
.liate{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:6px;margin:8px 0}
.liate span{border:1px solid var(--rule);border-radius:8px;background:var(--paper);padding:6px 4px;text-align:center;font-size:.74rem;line-height:1.35;color:var(--ink-2)}
.liate b{display:block;font:700 1.3rem var(--serif);color:var(--accent)}
.di{display:inline-block;margin:8px 0}
.di td,.di th{padding:6px 18px!important;text-align:center!important}
/* polynomial long division, lecture style */
.ldiv-wrap{overflow-x:auto;margin:10px 0 6px}
.ldiv{display:inline-grid;grid-template-columns:auto repeat(var(--n),auto);column-gap:.5em;row-gap:.3em;align-items:end;padding:14px 18px 12px;background:var(--paper);border:1px dashed var(--rule);border-radius:12px;font-size:1.05rem}
.ldiv > span{position:relative;text-align:right;padding:2px 5px;white-space:nowrap;min-height:1.6em}
.ldiv .q{color:var(--hl-p);font-weight:600}
.ldiv .note-q{font:500 .66rem var(--mono);color:var(--ink-3);align-self:center}
.ldiv .dv{border-right:2.2px solid var(--ink);border-bottom-right-radius:12px;padding-right:9px;font-weight:600}
.ldiv .top{border-top:2.2px solid var(--ink)}
.ldiv .sub{color:var(--ink-2)}
.ldiv .ul{border-bottom:1.5px solid var(--ink-2)}
.ldiv .op{font-size:.72em;color:var(--ink-3);text-align:left;align-self:center}
.ldiv .x::after,.ldiv .x2::after{content:"";position:absolute;left:6%;right:6%;top:52%;border-top:2.5px solid var(--red);transform:rotate(-24deg);border-radius:2px}
.ldiv .down i,.ldiv .rem i{display:block;font:700 .62rem/1.2 var(--sans);color:var(--red);font-style:normal;text-align:right}
.ldiv .rem{background:color-mix(in srgb,var(--ok) 16%,transparent);border-radius:6px}
.lesson .ld-notes{font-size:.9rem;margin:6px 0 6px}
.lesson .ld-notes li{margin-bottom:4px}
.vid-grid{display:grid;gap:16px;margin:12px 0 0}
@media (min-width:760px){.vid-grid{grid-template-columns:1fr 1fr}}
.vid-grid .facade h3{font-size:1rem}
/* Riemann sum lab */
.rs-lab{margin:18px 0}
.rs-ctl{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center;margin:6px 0 4px}
.rs-ctl label{display:flex;align-items:center;gap:6px;font-size:.88rem;color:var(--ink-2)}
.rs-ctl input.num{width:76px}
.rs-ctl select.num{width:auto}
.plot .rs-r{fill:color-mix(in srgb,var(--s-p1) 22%,transparent);stroke:var(--s-p1);stroke-width:1}
.plot .rs-r.neg{fill:color-mix(in srgb,var(--s-cur) 22%,transparent);stroke:var(--s-cur)}
.plot .rs-r.thin{stroke-width:.4}
.plot .rs-pt{fill:var(--s-p1);stroke:var(--card);stroke-width:1.5}
.rs-lab .stats{margin-top:8px}
@media print{.wx-bar,.rs-lab,.int-legend,.tf-filter{display:none!important}.practice .wx .steps,.practice .wx .answer{display:block!important}}
/* home: two reference cards side by side */
.ref-grid{display:grid;gap:18px}
@media (min-width:1100px){.ref-grid{grid-template-columns:1fr 1fr}.ref-grid .ref-card{grid-template-columns:1fr;padding:24px 26px}.ref-grid .ref-card svg{max-width:220px;margin:0}}
.ref-card .rc-area{fill:color-mix(in srgb,#2a78d6 22%,transparent);stroke:#2a78d6;stroke-width:1}
.ref-card .rc-curve{fill:none;stroke:#eb6834;stroke-width:3.5;stroke-linecap:round}
/* keep KaTeX's hidden MathML inside its scroll box (absolute children escape non-positioned scrollers) */
.table-wrap,.katex-display,.ldiv-wrap,.usub-map > div,.uv-x,.tt-cells i{position:relative}
@media (max-width:520px){
.lesson .steps > li{padding-left:34px}
.lesson .steps > li::before{width:24px;height:24px;font-size:.74rem}
.lesson .steps .katex-display > .katex,.int-page .tf .katex-display > .katex{font-size:.86em}
.wx{padding:14px 12px 10px}
.liate{grid-template-columns:repeat(5,minmax(52px,1fr))}
.ldiv{font-size:.8rem;padding:10px 8px;column-gap:.15em}
.ldiv > span{padding:2px 2px}
.ldiv .op{font-size:.6em}
}
/* ==========================================================================
LINEAR ALGEBRA — series nav, level badges, figures, formula index,
2×2 lab, product explainer, matrix calculator
========================================================================== */
.lesson.la-hub{max-width:none}
.la-page > header h1{margin-bottom:14px}
.lv{display:inline-block;font:600 .68rem/1.55 var(--mono);padding:1px 9px;border-radius:999px;vertical-align:middle;white-space:nowrap;letter-spacing:0}
.lv-b{background:color-mix(in srgb,var(--ok) 16%,var(--card));color:var(--ok)}
.lv-i{background:color-mix(in srgb,var(--signal) 15%,var(--card));color:var(--signal)}
.lv-a{background:color-mix(in srgb,#9b5de5 18%,var(--card));color:#7b3fc6}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) .lv-a{color:#c4a0f5}}
:root[data-theme="dark"] .lv-a{color:#c4a0f5}
.lesson h2 .lv{font-size:.66rem;margin-left:8px;transform:translateY(-4px)}
.lv-legend{display:flex;flex-wrap:wrap;gap:6px 16px;align-items:center;margin-top:14px;font-size:.84rem;color:var(--ink-2)}
.lv-legend .mono{color:var(--ink-3)}
.lv-legend > span{display:inline-flex;align-items:center;gap:6px}
.toc-lv{display:inline-block;width:7px;height:7px;border-radius:50%;margin-left:7px;vertical-align:middle}
.toc-lv.lv-b{background:var(--ok)} .toc-lv.lv-i{background:var(--signal)} .toc-lv.lv-a{background:#9b5de5}
.series-nav{display:flex;flex-direction:column;gap:6px;margin:0 0 18px}
.sn-title{color:var(--ink-3)}
.sn-list{display:flex;gap:6px;overflow-x:auto;padding-bottom:4px;scrollbar-width:thin}
@media (min-width:1000px){.sn-list{flex-wrap:wrap;overflow:visible}}
.sn-list a{flex:none;display:inline-flex;align-items:center;gap:7px;padding:6px 12px;border:1px solid var(--rule);border-radius:999px;background:var(--card);text-decoration:none;font-size:.86rem;color:var(--ink-2);white-space:nowrap}
.sn-list a:hover{border-color:var(--accent);color:var(--ink)}
.sn-list a[aria-current="page"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.sn-n{font:600 .72rem var(--mono);color:var(--accent)}
.tf.warn{border-color:color-mix(in srgb,var(--red) 40%,var(--rule));background:color-mix(in srgb,var(--red) 4%,var(--card))}
.la-check{margin:8px 0 0;padding-left:20px}
.la-check li{margin-bottom:6px}
.la-types td{font-size:.9rem}
.la-types small{color:var(--ink-3);font-family:var(--mono);font-size:.74rem}
.la-types .katex{font-size:.9em}
.la-patterns td{font-size:.9rem}
.la-page code{font-family:var(--mono);font-size:.85em;background:var(--paper-2);padding:1px 6px;border-radius:5px}
/* static figures */
.la-fig{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px;margin:16px 0;color:var(--ink)}
.la-fig svg{width:100%;max-width:600px;height:auto;margin:0 auto}
.la-fig figcaption{font-size:.84rem;color:var(--ink-3);text-align:center;margin-top:8px}
.la-fig text{font:500 15px var(--mono);fill:var(--ink)}
.la-fig .f-ent text{font:500 17px var(--sans)}
.la-fig .f-ent .hot{fill:var(--accent);font-weight:700}
.la-fig .f-ent .ghost{fill:var(--ink-3)}
.la-fig .t-th{font:500 13px var(--sans);fill:var(--ink-2)}
.la-fig .t-sm{font:500 12px var(--mono);fill:var(--ink-3)}
.la-fig .t-big{font:700 30px var(--serif);fill:var(--ink)}
.la-fig .t-mx{font:600 24px var(--mono);fill:var(--ink-2)}
.la-fig .c-p1{fill:var(--s-p1)} .la-fig .c-cur{fill:var(--s-cur)} .la-fig .c-p2{fill:var(--s-p2)}
.la-fig .f-br{fill:none;stroke:var(--ink);stroke-width:2}
.la-fig .f-row{fill:color-mix(in srgb,var(--s-p1) 16%,transparent)}
.la-fig .f-col{fill:color-mix(in srgb,var(--s-cur) 16%,transparent)}
.la-fig .f-ring{fill:none;stroke:var(--accent);stroke-width:2}
.la-fig .f-panel{fill:var(--paper);stroke:var(--rule)}
.la-fig .ax{stroke:var(--ink-3);stroke-width:1}
.la-fig .ln{fill:none;stroke:var(--ink-3);stroke-width:2;stroke-linecap:round}
.la-fig .ln-p1,.la-fig .ln-p1 path{stroke:var(--s-p1)} .la-fig .ln-cur,.la-fig .ln-cur path{stroke:var(--s-cur)} .la-fig .ln-p2{stroke:var(--s-p2)}
.la-fig .ln path{fill:none;stroke-width:2}
.la-fig .dash,.la-fig .dash path{stroke-dasharray:6 5}
.la-fig .thick{stroke-width:6;opacity:.45}
.la-fig .dot{fill:var(--accent);stroke:var(--card);stroke-width:2}
.la-flow div{font-size:.9rem}
/* hub: levels, page cards, help */
.la-levels{display:grid;gap:12px;margin:16px 0}
@media (min-width:860px){.la-levels{grid-template-columns:repeat(3,1fr)}}
.la-level{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px 16px}
.lesson .la-level h3{margin:8px 0 6px;font-size:1rem}
.lesson .la-level ul{padding-left:18px;margin:0;font-size:.9rem}
.la-level li{margin-bottom:5px}
.la-level a{color:var(--ink);text-decoration-color:var(--rule);text-underline-offset:3px}
.la-level a:hover{color:var(--accent)}
.la-cards{display:grid;gap:12px;margin:16px 0}
@media (min-width:640px){.la-cards{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1180px){.la-cards{grid-template-columns:repeat(3,1fr)}}
.la-card{display:flex;flex-direction:column;gap:4px;text-decoration:none;background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:18px;transition:transform .18s,border-color .18s,box-shadow .18s}
.la-card:hover{transform:translateY(-3px);border-color:var(--accent);box-shadow:var(--shadow)}
.la-card b{font-size:1.04rem;line-height:1.35}
.la-card .tc-sym{width:auto;min-width:42px;padding:0 8px;font-size:1rem}
.la-card .tc-foot .mono{color:var(--ink-3)}
.la-help{display:grid;gap:10px;margin:16px 0}
@media (min-width:640px){.la-help{grid-template-columns:repeat(2,1fr)}}
.la-help a{display:flex;flex-direction:column;gap:2px;padding:12px 14px;border:1px solid var(--rule);border-radius:12px;background:var(--card);text-decoration:none}
.la-help a:hover{border-color:var(--accent)}
.la-help b{font-weight:600;font-size:.95rem}
.la-help span{font-size:.84rem;color:var(--ink-3)}
/* formula index */
.fx-index .fx-tools{margin-top:12px}
.fx-chips{display:flex;flex-wrap:wrap;gap:6px;margin:10px 0}
.fx-chips button{font:500 .82rem var(--sans);padding:5px 12px;border-radius:999px;border:1px solid var(--rule);background:var(--card);color:var(--ink-2);cursor:pointer}
.fx-chips button[aria-pressed="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.lesson .fx-list{list-style:none;padding:0;margin:10px 0 0;display:grid;gap:8px;grid-template-columns:repeat(auto-fill,minmax(min(100%,330px),1fr))}
.lesson .fx-list > li{margin:0}
.fx{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:10px 14px 4px;min-width:0}
.fx-h{display:flex;flex-wrap:wrap;align-items:baseline;gap:2px 8px;text-decoration:none}
.fx-h b{font-weight:600;font-size:.92rem}
.fx-h:hover b{color:var(--accent)}
.fx-th{font-size:.82rem;color:var(--ink-3);width:100%}
.fx-f{overflow-x:auto;position:relative}
.fx-f .katex-display{margin:4px 0!important}
.fx-f .katex{font-size:.92em}
.fx-empty{color:var(--ink-3)}
.fx-more{margin-top:12px}
/* matrix display used by the tools */
.mxv{display:inline-grid;grid-template-columns:repeat(var(--c),auto);gap:0 12px;padding:4px 11px;position:relative;font:500 .9rem/1.55 var(--mono);vertical-align:middle;font-variant-numeric:tabular-nums;color:var(--ink)}
.mxv::before,.mxv::after{content:"";position:absolute;top:0;bottom:0;width:6px;border:1.6px solid var(--ink)}
.mxv::before{left:0;border-right:0;border-radius:5px 0 0 5px}
.mxv::after{right:0;border-left:0;border-radius:0 5px 5px 0}
.mxv.vbar::before{border:0;border-left:1.6px solid var(--ink);border-radius:0}
.mxv.vbar::after{border:0;border-right:1.6px solid var(--ink);border-radius:0}
.mxv > span{text-align:right;min-width:1.3em;padding:1px 3px;border-radius:4px;white-space:nowrap}
.mxv > span.sep{border-left:1.5px solid var(--ink-3);border-radius:0;padding-left:9px}
.mxv > span.pv{background:color-mix(in srgb,var(--hl-p,#2a78d6) 22%,transparent)}
.mxv > span.rep{background:color-mix(in srgb,var(--hl-u,#1baf7a) 24%,transparent)}
.fr{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;line-height:1.05;font-size:.8em}
.fr i{font-style:normal}
.fr i:first-child{border-bottom:1px solid currentColor;padding:0 2px}
/* product explainer */
.mx-prod{background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:14px 16px;margin:16px 0}
.lesson .mxp-h{margin:0 0 10px;font-size:.92rem;color:var(--ink-2)}
.mxp-row{display:flex;flex-wrap:wrap;align-items:center;gap:10px 14px}
.mxp-cell{display:flex;flex-direction:column;align-items:center;gap:4px}
.mxp-cell .mono{color:var(--ink-3)}
.mxp-op{font:600 1.3rem var(--serif);color:var(--ink-3)}
.mxp-a > span.on{background:color-mix(in srgb,var(--s-p1) 26%,transparent)}
.mxp-b > span.on{background:color-mix(in srgb,var(--s-cur) 26%,transparent)}
.mxp-c button{font:inherit;border:1px dashed var(--ink-3);background:var(--paper);color:var(--ink);border-radius:6px;padding:1px 8px;cursor:pointer;min-width:2.4em;text-align:right}
.mxp-c button.on{background:var(--accent);color:var(--accent-ink);border:1px solid var(--accent)}
.lesson .mxp-sum{font-variant-numeric:tabular-nums;font-size:.92rem;margin:12px 0 0;padding:8px 12px;border-radius:8px;background:var(--paper-2);overflow-x:auto;white-space:nowrap}
/* 2×2 lab */
.la-lab{display:grid;gap:14px;background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:14px;margin:16px 0}
@media (min-width:760px){.la-lab{grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);align-items:start}}
.lab-fig svg{width:100%;height:auto;max-width:420px;margin:0 auto;background:var(--paper);border-radius:10px;touch-action:pan-y;user-select:none;-webkit-user-select:none}
.lesson .lab-fig .hint{text-align:center}
.lab-mx{display:flex;align-items:center;gap:10px}
.lab-in{display:grid;grid-template-columns:repeat(2,76px);gap:6px;padding:6px 9px;border-left:2px solid var(--ink);border-right:2px solid var(--ink);border-radius:8px}
.lab-in .num{text-align:center}
.lab-pre{display:flex;flex-wrap:wrap;gap:6px;margin:12px 0}
.lab-pre button{font:500 .8rem var(--sans);padding:5px 10px;border:1px solid var(--rule);border-radius:999px;background:var(--paper);color:var(--ink-2);cursor:pointer}
.lab-pre button:hover{border-color:var(--accent);color:var(--ink)}
.lab-read .lr{display:flex;justify-content:space-between;gap:10px;padding:6px 0;border-bottom:1px dashed var(--rule);font-size:.92rem}
.lab-read .lr b{font-family:var(--mono);text-align:right}
.lesson .lr-note{margin:8px 0 0;font-size:.86rem;color:var(--ink-2);padding:8px 10px;border-radius:8px;background:var(--paper-2)}
.lesson .lr-note.ok{background:color-mix(in srgb,var(--ok) 16%,transparent);color:var(--ink);font-weight:600}
.la-lab .lg-g{stroke:var(--rule);stroke-width:.8}
.la-lab .lg-ax{stroke:var(--ink-3);stroke-width:1.2}
.la-lab .lg-tg{stroke:color-mix(in srgb,var(--s-p1) 32%,transparent);stroke-width:1}
.la-lab .lg-unit{fill:none;stroke:var(--ink-3);stroke-width:1.4;stroke-dasharray:4 4}
.la-lab .lg-par{stroke-width:2}
.la-lab .lg-par.pos{fill:color-mix(in srgb,var(--s-p1) 20%,transparent);stroke:var(--s-p1)}
.la-lab .lg-par.neg{fill:color-mix(in srgb,var(--s-cur) 22%,transparent);stroke:var(--s-cur)}
.la-lab .lg-par.zero{fill:none;stroke:var(--ink-3)}
.la-lab .lv-area{font:700 15px var(--mono);fill:var(--ink);paint-order:stroke;stroke:var(--paper);stroke-width:4px;stroke-linejoin:round}
.la-lab .lg-circ{fill:none;stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:3 4}
.la-lab .lg-ell{fill:color-mix(in srgb,var(--hl-c) 8%,transparent);stroke:var(--hl-c);stroke-width:1.6}
.la-lab .lg-eig{stroke:var(--s-p2);stroke-width:2.2;stroke-dasharray:8 5}
.la-lab .lv-eiglab{font:600 12px var(--mono);fill:var(--s-p2);paint-order:stroke;stroke:var(--paper);stroke-width:4px;stroke-linejoin:round}
.la-lab .lv-arr{stroke-width:3;stroke-linecap:round}
.la-lab .lv-lab{font:600 12px var(--sans);paint-order:stroke;stroke:var(--paper);stroke-width:4px;stroke-linejoin:round}
.la-lab line.c-a1{stroke:var(--s-cur)} .la-lab path.c-a1,.la-lab text.c-a1{fill:var(--s-cur)}
.la-lab line.c-a2{stroke:var(--s-p1)} .la-lab path.c-a2,.la-lab text.c-a2{fill:var(--s-p1)}
.la-lab line.c-v{stroke:var(--ink)} .la-lab path.c-v,.la-lab text.c-v{fill:var(--ink)}
.la-lab line.c-av{stroke:var(--hl-c)} .la-lab path.c-av,.la-lab text.c-av{fill:var(--hl-c)}
.la-lab .lg-vh{fill:var(--ink);stroke:var(--paper);stroke-width:2}
.la-lab .lg-hit{fill:transparent;touch-action:none;cursor:grab}
.la-lab .lg-hit:hover{fill:color-mix(in srgb,var(--accent) 14%,transparent)}
/* matrix calculator */
.mx-calc{background:var(--card);border:1.5px solid var(--ink);border-radius:14px;padding:14px;margin:16px 0}
.mc-top{display:flex;flex-wrap:wrap;gap:10px;align-items:center;justify-content:space-between}
.mc-modes{flex:1 1 320px}
.mc-size{display:flex;align-items:center;gap:8px;font-size:.9rem;color:var(--ink-2)}
.mc-size select{font:500 .9rem var(--mono);padding:6px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.mc-in{display:flex;flex-wrap:wrap;gap:14px 18px;align-items:center;margin:14px 0 8px}
.mc-blk{display:flex;gap:8px;align-items:center}
.mc-blk > .mono{font:600 1rem var(--mono);color:var(--ink-2)}
.mc-grid{display:grid;grid-template-columns:repeat(var(--n),minmax(46px,64px));gap:6px;padding:8px 10px;border-left:2px solid var(--ink);border-right:2px solid var(--ink);border-radius:10px}
.mc-bgrid{display:grid;grid-template-columns:minmax(46px,64px);gap:6px;padding:8px 10px;border-left:2px solid var(--ink);border-right:2px solid var(--ink);border-radius:10px}
.mc-in .num{text-align:center;font-size:.95rem;padding:7px 4px}
.mc-in .num.bad{border-color:#d14343;background:color-mix(in srgb,#d14343 8%,var(--paper))}
.mc-actions{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center}
.lesson .mc-actions .hint{margin:0}
.mc-out{margin-top:12px}
.mc-ans{border:1px solid color-mix(in srgb,var(--ok) 45%,transparent);background:color-mix(in srgb,var(--ok) 8%,var(--card));border-radius:12px;padding:12px 14px;overflow-x:auto}
.mc-ans.bad{border-color:color-mix(in srgb,#d14343 45%,transparent);background:color-mix(in srgb,#d14343 6%,var(--card))}
.mc-ans > .mono{color:var(--ink-3);display:block;margin-bottom:4px}
.lesson .mc-ans .hint,.lesson .mc-det .hint{margin:6px 0 0}
.mc-sol{display:flex;flex-wrap:wrap;gap:6px 22px;font-size:1.08rem}
.mc-sol b,.mc-eigs b{font-family:var(--mono)}
.mc-eigs{display:flex;flex-direction:column;gap:4px;font-size:1.02rem}
.mc-eigs small{color:var(--ink-3);font-size:.8rem}
.mc-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:6px 0}
.mc-frac{font:600 .95rem var(--mono)}
.mc-det{margin-top:10px;border-top:1px dashed var(--rule);padding-top:8px}
.mc-det summary{cursor:pointer;color:var(--signal);font-weight:600;font-size:.95rem}
.mc-det > .mxv{margin:10px 0 0}
.lesson .mc-steps{list-style:none;counter-reset:ms;padding:0;margin:10px 0 0}
.lesson .mc-steps > li{counter-increment:ms;position:relative;padding:8px 0 10px 36px;margin:0;border-bottom:1px dashed var(--rule);overflow-x:auto}
.mc-steps > li::before{content:counter(ms);position:absolute;left:0;top:9px;width:24px;height:24px;border-radius:50%;background:var(--ink);color:var(--paper);display:grid;place-items:center;font:600 .74rem var(--mono)}
.lesson .mc-op{margin:0 0 6px;font:500 .86rem/1.6 var(--mono);color:var(--accent)}
.lesson .mc-terms{padding-left:18px;margin:8px 0}
.lesson .mc-terms li{margin-bottom:10px;overflow-x:auto}
.lesson .mc-line{font-family:var(--mono);font-size:.92rem;margin:6px 0;overflow-x:auto}
.mc-err{color:#c43c3c}
@media (max-width:520px){
.mc-grid{grid-template-columns:repeat(var(--n),minmax(40px,1fr));padding:6px}
.mc-in .num{font-size:.88rem;padding:6px 2px}
.mxv{font-size:.8rem;gap:2px 8px}
}
/* home: linear algebra feature */
.la-feature{display:grid;gap:24px;align-items:center;background:var(--card);border:1px solid var(--rule);border-radius:18px;padding:22px;box-shadow:var(--shadow)}
@media (min-width:900px){.la-feature{grid-template-columns:330px 1fr;padding:28px 32px;gap:36px}}
.la-feature svg{width:100%;max-width:330px;height:auto;margin:0 auto;display:block}
.la-feature h3{font:700 clamp(1.35rem,2.8vw,1.75rem)/1.3 var(--serif);margin:6px 0 10px}
.la-feature p{margin:0 0 14px;color:var(--ink-2)}
.la-feature .la-stats{display:flex;flex-wrap:wrap;gap:6px 18px;margin:0 0 14px;padding:0;list-style:none;font:500 .84rem var(--mono);color:var(--ink-3)}
.la-feature .la-stats b{color:var(--accent);font-weight:600}
.la-feature .hf-g{stroke:var(--rule);stroke-width:1}
.la-feature .hf-ax{stroke:var(--ink-3);stroke-width:1.2}
.la-feature .hf-unit{fill:none;stroke:var(--ink-3);stroke-width:1.4;stroke-dasharray:4 4}
.la-feature .hf-par{fill:color-mix(in srgb,#2a78d6 18%,transparent);stroke:#2a78d6;stroke-width:2}
.la-feature .hf-eig{stroke:#1baf7a;stroke-width:2.4;stroke-dasharray:8 5}
.la-feature .hf-a1{stroke:#eb6834;stroke-width:3.5;stroke-linecap:round}
.la-feature .hf-a2{stroke:#2a78d6;stroke-width:3.5;stroke-linecap:round}
.la-feature text{font:600 13px var(--mono);fill:var(--ink-2);paint-order:stroke;stroke:var(--card);stroke-width:4px;stroke-linejoin:round}
.la-feature text.g{fill:#1baf7a} .la-feature text.o{fill:#eb6834} .la-feature text.b{fill:#2a78d6}
@media print{.mx-calc,.la-lab,.series-nav,.fx-tools,.fx-chips,.mxp-h{display:none!important}}
/* desktop nav: one more top-level link (พีชคณิตเชิงเส้น) — tighten on mid-size screens, widen the bar on large ones */
/* 2026-10-12: more top-level links (แล็บ FG + สโคป, อนุกรมฟูเรียร์) — the inline menu starts at 1900 px (was 1600 until 2026-10-24), hamburger below that */
/* full desktop menu needs ~1850 px; below 2000 px the brand shows only its mark so the row never overlaps (2026-10-24) */
@media (min-width:1900px) and (max-width:2299px){.nav .wrap{padding:0 20px;max-width:none}.nav-links{gap:11px;font-size:.86rem}.brand small{display:none}}
@media (min-width:1900px) and (max-width:1999px){.brand > span:last-child{display:none}}
@media (min-width:2300px){.nav .wrap{max-width:2200px}}
/* ==========================================================================
FG + OSCILLOSCOPE LAB (/learn/function-generator/)
========================================================================== */
.fgs-bench,.fgs-mini{--c1:#f6d32d;--c2:#2ed3e6;--lcd:#0c1b24;--lcd-ink:#9fe6ff;--panel:color-mix(in srgb,var(--card) 70%,var(--paper-2))}
.fgs-bench{margin:8px 0 28px}
.fgs-bar{display:flex;flex-wrap:wrap;align-items:center;gap:8px 10px;margin:0 0 14px;padding:10px 12px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.fgs-bar label{color:var(--ink-3)}
.fgs-bar .pre{flex:1 1 220px;min-width:0}
.pre{font:inherit;font-size:.92rem;padding:7px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);max-width:100%}
.fgs-grid{display:grid;gap:16px}
@media (min-width:1100px){.fgs-grid{grid-template-columns:minmax(0,1.55fr) minmax(330px,1fr);align-items:start}}
.fgs-side{display:grid;gap:16px;min-width:0}
.inst{background:var(--panel);border:1px solid var(--rule);border-radius:16px;padding:12px;box-shadow:var(--shadow);min-width:0}
.inst-head{display:flex;justify-content:space-between;align-items:baseline;gap:10px;flex-wrap:wrap;margin:0 2px 10px}
.inst-head b{font:600 .82rem var(--mono);letter-spacing:.08em}
.inst-head .mono{color:var(--ink-3);font-size:.7rem}
.sc-screen{background:#0b1014;border-radius:10px;padding:0;overflow:hidden;border:3px solid #1b232b;box-shadow:inset 0 0 0 1px #000}
.sc-screen canvas{display:block;width:100%;height:auto;touch-action:pan-y}
.sc-run{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin:10px 0}
.sc-inl{display:inline-flex;align-items:center;gap:6px}
.sc-inl > .mono{color:var(--ink-3);font-size:.68rem}
.sc-btn{font:600 .78rem var(--mono);padding:8px 12px;border-radius:8px;border:1px solid var(--rule);background:var(--card);color:var(--ink);cursor:pointer;letter-spacing:.03em}
.sc-btn:hover{border-color:var(--ink-3)}
.sc-btn.run{background:#1f7a3a;border-color:#1f7a3a;color:#fff}
.sc-btn.run.stopped{background:#b42318;border-color:#b42318}
.sc-btn.auto{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.sc-btn.chbtn[aria-pressed="false"]{opacity:.6}
.sc-panels{display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(min(100%,230px),1fr))}
.sc-p{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:10px;display:grid;gap:8px;align-content:start;min-width:0}
.sc-p h4{margin:0;font-size:.72rem;color:var(--ink-3);letter-spacing:.08em}
.sc-ch.c1{border-top:3px solid var(--c1)} .sc-ch.c2{border-top:3px solid var(--c2)}
.sc-p .mono.c1{color:#b39400} .sc-p .mono.c2{color:#0e8fa0}
.sc-row{display:flex;flex-wrap:wrap;gap:6px;align-items:center}
.sc-row > .mono{font-size:.7rem;color:var(--ink-3)}
.sc-p .seg,.mini-ctl .seg{width:100%}
.sc-row .seg{width:auto;flex:1 1 auto}
.kn-pair{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:flex-end}
.kn{display:grid;justify-items:center;gap:2px;min-width:92px}
.kn-l{font:500 .7rem var(--mono);color:var(--ink-3);text-align:center}
.kn-row{display:flex;align-items:center;gap:4px}
.kn-dial{--a:0deg;--kc:var(--ink-2);position:relative;width:46px;height:46px;border-radius:50%;cursor:grab;touch-action:none;
background:radial-gradient(circle at 35% 30%,#5b6670,#262d34 62%,#14191e);box-shadow:0 2px 5px rgba(0,0,0,.35),inset 0 1px 0 rgba(255,255,255,.15);outline-offset:3px}
.kn-dial::before{content:"";position:absolute;inset:-5px;border-radius:50%;border:2px dotted color-mix(in srgb,var(--kc) 55%,transparent)}
.kn-dial i{position:absolute;left:50%;top:5px;width:3px;height:15px;margin-left:-1.5px;border-radius:2px;background:var(--kc);transform-origin:50% 18px;transform:rotate(var(--a));transition:transform .08s}
.kn-big .kn-dial{width:58px;height:58px}
.kn-big .kn-dial i{transform-origin:50% 24px;height:18px}
.kn-b{width:28px;height:28px;border-radius:7px;border:1px solid var(--rule);background:var(--paper);color:var(--ink);font:600 .95rem var(--mono);cursor:pointer;padding:0;line-height:1}
.kn-b:hover{border-color:var(--ink-3)}
.kn-v{font:600 .78rem var(--mono);color:var(--ink);white-space:nowrap}
.sc-meas{margin-top:10px;overflow-x:auto}
table.meas{width:100%;border-collapse:collapse;font-size:.84rem;background:var(--card);border:1px solid var(--rule);border-radius:10px;overflow:hidden}
table.meas th,table.meas td{padding:5px 10px;border-bottom:1px solid var(--rule);text-align:left;white-space:nowrap}
table.meas thead th{font:500 .72rem var(--mono);color:var(--ink-3);background:var(--paper-2)}
table.meas thead th.c1{box-shadow:inset 0 -3px 0 var(--c1)} table.meas thead th.c2{box-shadow:inset 0 -3px 0 var(--c2)}
table.meas tbody th{font-weight:500;color:var(--ink-2)}
table.meas td{font-family:var(--mono);font-size:.82rem}
table.meas td.clip{color:#c43c3c}
table.meas tr.ph td{white-space:normal}
.cur{margin:8px 0 0;padding:8px 10px;border-radius:8px;background:color-mix(in srgb,#ff8a3d 12%,transparent);font-size:.8rem;overflow-x:auto}
/* function generator */
.fg-lcd{background:var(--lcd);color:var(--lcd-ink);border-radius:10px;padding:10px 12px;border:3px solid #1b232b;font-family:var(--mono);min-height:120px}
.fg-top{font-size:.7rem;color:#7fb7c9}
.fg-top b{color:#e6f6ff}
.fg-top .on{color:#7ee787} .fg-top .off{color:#ff7b72}
.fg-main{margin:6px 0 4px;font:600 clamp(1.5rem,5vw,2rem)/1.15 var(--mono);color:#e6f6ff;letter-spacing:.02em;overflow-x:auto;white-space:nowrap}
.fg-main u{text-decoration:none;border-bottom:3px solid #ffb86b}
.fg-main small{font-size:.5em;color:var(--lcd-ink)}
.fg-pn{display:block;font:500 .7rem var(--mono);color:#7fb7c9;letter-spacing:.06em}
.fg-list{display:flex;flex-wrap:wrap;gap:2px 14px;font-size:.74rem}
.fg-list b{color:#e6f6ff;font-weight:500}
.fg-list .warn{color:#ffb86b}
.fg-msg{margin-top:6px;font-size:.74rem;color:#ffb86b}
.fg-sec{margin-top:10px}
.fg-h{display:block;font-size:.68rem;color:var(--ink-3);margin:0 0 6px;letter-spacing:.06em}
.fg-waves,.fg-params{display:flex;flex-wrap:wrap;gap:5px}
.fg-key,.fg-soft{font:600 .78rem var(--mono);padding:7px 9px;border-radius:8px;border:1px solid var(--rule);background:var(--card);color:var(--ink-2);cursor:pointer}
.fg-key[aria-pressed="true"],.fg-soft[aria-pressed="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.fg-soft small{display:block;font:500 .64rem var(--sans);opacity:.75}
.fg-in{display:flex;gap:6px}
.fg-in input{flex:1 1 auto;min-width:0;font:500 .95rem var(--mono);padding:8px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.fg-dig{display:flex;align-items:center;justify-content:center;gap:14px;margin-top:8px}
.fg-dig .kn{min-width:0}
.fg-dig .kn-l,.fg-dig .kn-v,.fg-dig .kn-row .kn-b{display:none}
.fg-entry .hint code{font-family:var(--mono);font-size:.9em;background:var(--paper-2);padding:0 4px;border-radius:4px}
.fg-mp{display:grid;grid-template-columns:1fr 110px 34px;gap:6px;align-items:center;margin-top:6px;font-size:.84rem;color:var(--ink-2)}
.fg-mp input{font:500 .86rem var(--mono);padding:5px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);min-width:0}
.fg-modp .seg{margin-top:6px}
.fg-outrow{display:grid;grid-template-columns:1fr 1fr;gap:10px;align-items:end}
.fg-outbtn{grid-column:1/-1;font:700 .85rem var(--mono);padding:10px;border-radius:10px;border:0;cursor:pointer;background:#3a4148;color:#cfd6dc;letter-spacing:.08em}
.fg-outbtn[aria-pressed="true"]{background:#1f7a3a;color:#fff;box-shadow:0 0 0 3px color-mix(in srgb,#3fb950 35%,transparent)}
/* circuit board */
.dut-inst select{width:100%}
.dut-l{display:block;font-size:.84rem;color:var(--ink-2);margin:2px 0 4px}
.dut-sch{background:var(--card);border:1px solid var(--rule);border-radius:10px;margin:10px 0;padding:6px;color:var(--ink)}
.sch{width:100%;height:auto;display:block}
.sch .sw{fill:none;stroke:currentColor;stroke-width:1.8;stroke-linejoin:round;stroke-linecap:round}
.sch text{font:500 11px var(--mono);fill:currentColor}
.sch .s-sm{font-size:10.5px;fill:var(--ink-2)}
.sch .s-c{text-anchor:middle}
.sch .s-warn{fill:#c43c3c}
.sch .s-box{fill:var(--paper-2);stroke:currentColor;stroke-width:1.5}
.sch .s-fg{font:700 13px var(--mono);text-anchor:middle}
.sch .s-pm{font:700 13px var(--mono)}
.sch .s-ch1{fill:#e0b400;stroke:var(--card);stroke-width:1.5} .sch .s-ch2{fill:#14b8cc;stroke:var(--card);stroke-width:1.5}
.sch .s-cht1{fill:#b39400;font-weight:700} .sch .s-cht2{fill:#0e8fa0;font-weight:700}
.dut-row{margin-top:8px}
.dut-num{display:flex;gap:6px;align-items:center}
.dut-num input{flex:1 1 auto;min-width:0;font:500 .9rem var(--mono);padding:6px 9px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink)}
.dut-num .mono{color:var(--ink-3);min-width:16px}
.dut-ck{display:flex;gap:8px;align-items:center;font-size:.9rem;cursor:pointer}
.dut-th{list-style:none;margin:10px 0 0;padding:10px 12px;border-radius:10px;background:color-mix(in srgb,var(--signal) 9%,transparent);display:grid;gap:4px;font-size:.84rem}
.dut-th li{display:flex;flex-wrap:wrap;justify-content:space-between;gap:2px 10px;margin:0}
.dut-th li span{color:var(--ink-2)}
.dut-th li b{font-family:var(--mono);font-weight:600}
.dut-th .fid{text-decoration:none;font-size:.66rem}
.dut-th li.warn{color:#c43c3c;display:block}
.hint.warn{color:#c43c3c}
/* small embedded scope inside lessons */
.fgs-mini{display:grid;gap:12px;margin:18px 0;padding:12px;border:1px solid var(--rule);border-radius:14px;background:var(--panel)}
@media (min-width:860px){.fgs-mini{grid-template-columns:minmax(0,1.35fr) minmax(250px,1fr);align-items:start}}
.mini-body{display:grid;gap:10px;min-width:0}
.mini-ctl{display:grid;gap:4px}
.mini-ctl .row{margin-top:4px}
.mini-l{font-size:.86rem;color:var(--ink-2)}
.mini-ctl .kn-pair,.mini-ctl > .kn{justify-self:start}
.mini-ctl > .kn{display:inline-grid}
.mini-meas{overflow-x:auto}
.mini-foot{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.mini-open{margin-left:auto;font-size:.88rem;color:var(--signal);text-decoration:none}
.fgs-mini noscript,.fgs-bench noscript{display:block;padding:12px;color:var(--ink-3)}
.fgs-mini:not(.fgs-ready){min-height:260px}
.fgs-bench:not(.fgs-ready){min-height:420px}
.fg-ph{display:grid;place-items:center;min-height:240px;border-radius:12px;background:#0b1014;color:#8b949e;font:500 .9rem var(--mono)}
/* lesson figures for this series */
.fgfig{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px;margin:16px 0;color:var(--ink)}
.fgfig svg{width:100%;max-width:640px;height:auto;margin:0 auto;display:block}
.fgfig figcaption{font-size:.84rem;color:var(--ink-3);text-align:center;margin-top:8px}
.fgfig .ax{stroke:var(--ink-3);stroke-width:1.2;fill:none}
.fgfig .gr{stroke:var(--rule);stroke-width:1;fill:none}
.fgfig .w1{fill:none;stroke:#d9a400;stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}
.fgfig .w2{fill:none;stroke:#0fa3b8;stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}
.fgfig .w3{fill:none;stroke:var(--accent);stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}
.fgfig .dsh{fill:none;stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:5 4}
.fgfig .acc{fill:none;stroke:var(--accent);stroke-width:1.6}
.fgfig .ar{fill:none;stroke:var(--ink);stroke-width:1.3}
.fgfig .bx{fill:var(--paper-2);stroke:var(--ink);stroke-width:1.4}
.fgfig .bx2{fill:color-mix(in srgb,var(--signal) 12%,var(--card));stroke:var(--signal);stroke-width:1.4}
.fgfig .ar-h{fill:var(--ink)}
.fgfig .fill1{fill:color-mix(in srgb,#d9a400 22%,transparent)}
.fgfig .fill2{fill:color-mix(in srgb,#0fa3b8 18%,transparent)}
.fgfig text{font:500 13px var(--mono);fill:var(--ink-2)}
.fgfig text.t{font:600 13px var(--sans);fill:var(--ink)}
.fgfig text.s{font-size:11.5px;fill:var(--ink-3)}
.fgfig text.a{fill:var(--accent);font-weight:600}
.fgfig text.c1{fill:#b39400;font-weight:600} .fgfig text.c2{fill:#0e8fa0;font-weight:600}
.fgfig .scr{fill:#0b1014}
.fgfig .sgr{stroke:rgba(200,210,220,.22);stroke-width:1;stroke-dasharray:1 3;fill:none}
.fgfig .sw1{fill:none;stroke:#f6d32d;stroke-width:2.2}
.fgfig .sw2{fill:none;stroke:#2ed3e6;stroke-width:2.2}
.fgfig text.st{fill:#e6edf3;font-size:11px}
.fgfig .sw{fill:none;stroke:currentColor;stroke-width:1.8;stroke-linejoin:round;stroke-linecap:round}
.ws-list{display:grid;gap:12px;margin:16px 0;counter-reset:ws}
.ws{border:1px solid var(--rule);border-radius:14px;background:var(--card);padding:14px 16px;counter-increment:ws}
.ws h3{margin:0 0 6px!important;font-size:1.05rem}
.ws h3::before{content:"ใบงาน " counter(ws) " · ";color:var(--accent);font-family:var(--mono);font-size:.8rem;font-weight:500}
.ws p,.ws li{font-size:.94rem}
.ws ol{margin:6px 0 8px}
.ws .ws-go{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin-top:8px}
.ws .ws-ans{border-top:1px dashed var(--rule);margin-top:8px;padding-top:6px}
.ws .ws-ans summary{cursor:pointer;color:var(--signal);font-weight:600;font-size:.92rem}
.lab-page .lesson-wrap.fg-lab-wrap{max-width:1440px}
.fg-hub-hero{display:grid;gap:18px;align-items:center;margin:20px 0 6px;padding:18px;border:1px solid var(--rule);border-radius:16px;background:var(--card);box-shadow:var(--shadow)}
@media (min-width:860px){.fg-hub-hero{grid-template-columns:1.2fr 1fr}}
.fg-hub-hero svg{width:100%;height:auto;display:block;border-radius:12px}
.fg-hub-hero h3{margin:0 0 8px;font:700 1.3rem/1.35 var(--serif)}
.fg-hub-hero p{margin:0 0 12px;color:var(--ink-2)}
@media print{.fgs-bench,.fgs-mini{display:none!important}}
.fg-calc{border:1px solid var(--rule);border-left:4px solid var(--signal);border-radius:12px;background:var(--card);padding:12px 16px;margin:18px 0}
.lesson .fg-calc .fc-t{margin:0 0 8px;display:flex;flex-wrap:wrap;gap:4px 10px;align-items:baseline}
.fg-calc .fc-t .mono{color:var(--ink-3);font-size:.74rem}
.fc-in{display:grid;gap:8px;grid-template-columns:repeat(auto-fill,minmax(min(100%,190px),1fr))}
.fc-in label{display:grid;grid-template-columns:1fr auto;gap:2px 6px;align-items:center;font-size:.84rem;color:var(--ink-2)}
.fc-in label span{grid-column:1/-1}
.fc-in input,.fc-in select{font:500 .9rem var(--mono);padding:6px 9px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);min-width:0;width:100%}
.fc-in i{font:normal .78rem var(--mono);color:var(--ink-3)}
.fc-out{display:grid;grid-template-columns:auto 1fr;gap:4px 14px;margin:12px 0 0;padding:10px 12px;border-radius:8px;background:color-mix(in srgb,var(--signal) 8%,transparent);font-size:.88rem}
.fc-out dt{color:var(--ink-2)} .fc-out dd{margin:0;font-family:var(--mono);font-weight:600;text-align:right}
@media print{.fg-calc{display:none}}
/* DDS phase-accumulator visualiser (build-your-own page) */
.dds-lab{display:grid;gap:12px;margin:18px 0;padding:12px;border:1px solid var(--rule);border-radius:14px;background:color-mix(in srgb,var(--card) 70%,var(--paper-2))}
.dds-ctl{display:grid;gap:4px 18px;grid-template-columns:repeat(auto-fit,minmax(min(100%,220px),1fr));align-items:start}
.dds-ctl .dds-btns,.dds-ctl .dds-out{grid-column:1/-1}
.dds-ctl .row{margin-top:4px}
.dds-lab .dds-fig{margin:0;padding:8px}
.dds-lab .dds-fig svg{max-width:none}
.dds-btns{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}
.dds-out{font-size:.82rem}
@media print{.dds-lab{display:none}}
.lesson pre.code{overflow:auto;background:#0f1720;color:#e6edf3;padding:14px 16px;border-radius:12px;font:500 .8rem/1.6 var(--mono);margin:14px 0;tab-size:2;max-width:100%}
.lesson pre.code .c{color:#8b949e}
.lesson pre.code + .hint{margin-top:-6px}
/* home: new-section pill + FG feature */
.hero-new{display:inline-flex;align-items:center;gap:8px;margin:0 0 14px;padding:6px 14px 6px 8px;border:1px solid color-mix(in srgb,var(--accent) 40%,var(--rule));border-radius:999px;background:color-mix(in srgb,var(--accent) 8%,var(--card));font-size:.9rem;color:var(--ink);text-decoration:none;max-width:100%}
.hero-new b{background:var(--accent);color:#fff;border-radius:999px;padding:2px 8px;font:600 .72rem var(--mono);letter-spacing:.04em}
.hero-new:hover{border-color:var(--accent)}
.hero-new > span{min-width:0}
.hero-new b{white-space:nowrap}
@media (min-width:900px){.la-feature.fg-feature{grid-template-columns:minmax(0,1fr) minmax(0,1.05fr)}}
.la-feature .fg-feature-fig{margin:0;padding:0;border:0;background:none}
.la-feature .fg-feature-fig svg{max-width:none}
.lab-card .lab-fig{display:block;margin:0;padding:0;border:0;background:none}
.lab-card .lab-fig svg{background:#0b1014}
@media (min-width:1100px){#labs .lab-cards{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1360px){#labs .lab-cards{grid-template-columns:repeat(4,1fr)}}
/* ============================================================ Control systems series */
:root{--b1:#2a78d6;--b2:#d9541e;--b3:#1a9a6c;--b4:#9b5de5;--b5:#c28a00;--b6:#0d93a8;--bad:#d03a2f;--warnc:#b97800}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){--b1:#5aa0f0;--b2:#f08a56;--b3:#4cc296;--b4:#b98af0;--b5:#e6b422;--b6:#40c1d4;--bad:#ff7468;--warnc:#e6b422}}
:root[data-theme="dark"]{--b1:#5aa0f0;--b2:#f08a56;--b3:#4cc296;--b4:#b98af0;--b5:#e6b422;--b6:#40c1d4;--bad:#ff7468;--warnc:#e6b422}
/* series nav with parts */
.series-nav .sn-part{display:flex;flex-direction:column;gap:4px}
.sn-pt{font-size:.72rem;color:var(--ink-3);letter-spacing:.02em}
.sn-all{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:0}
.sn-all > summary{cursor:pointer;padding:9px 14px;font-size:.88rem;font-weight:600;color:var(--ink-2);list-style:none}
.sn-all > summary::-webkit-details-marker{display:none}
.sn-all > summary::after{content:" ▾";color:var(--accent)}
.sn-all[open] > summary::after{content:" ▴"}
.sn-all .sn-part{padding:6px 14px 10px;border-top:1px solid var(--rule)}
.sn-all .sn-list{flex-wrap:wrap;overflow:visible}
/* hub: grouped cards */
.cs-part{margin:30px 0 8px}
.cs-part-h{display:grid;gap:2px;margin-bottom:10px}
.cs-part-h h3{margin:0;font-size:1.2rem;line-height:1.3}
.cs-part-h h3 small{font:500 .78rem var(--mono);color:var(--ink-3);margin-left:8px}
.cs-part-h p{margin:0;color:var(--ink-2);font-size:.95rem}
.cs-part-n{color:var(--accent);font-size:.74rem}
.cs-part-soon{color:var(--ink-3)}
.la-card.soon{opacity:.62;border-style:dashed;cursor:default}
.la-card.soon:hover{transform:none;border-color:var(--rule);box-shadow:none}
.la-card.soon .soon-tag{font:600 .7rem var(--mono);color:var(--ink-3);border:1px solid var(--rule);border-radius:999px;padding:1px 8px;align-self:flex-start}
/* interactive lab */
.cs-lab{margin:20px 0;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px;display:grid;gap:10px;min-width:0}
.cs-lab:not(.cs-ready){min-height:120px}
.cs-bar{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center}
.cs-f{display:inline-flex;align-items:center;gap:8px;font-size:.88rem}
.cs-f .mono{color:var(--ink-3);font-size:.78rem}
.cs-f-tf{flex:1 1 280px}
.cs-tf{flex:1;min-width:0;font:500 .95rem var(--mono);padding:8px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.cs-pre,.cs-kn{font:inherit;font-size:.9rem;padding:7px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.cs-kn{width:92px;font-family:var(--mono)}
.cs-f-k{flex:1 1 260px}
.cs-kr{flex:1;min-width:90px;accent-color:var(--accent)}
.cs-btn{font:600 .8rem var(--sans);padding:6px 12px;border-radius:999px;border:1px solid var(--rule);background:var(--paper);color:var(--signal);cursor:pointer}
.cs-btn:hover{border-color:var(--signal)}
.cs-btn[aria-pressed="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.cs-btn.cs-sm{padding:1px 9px;font-size:.78rem}
.cs-zoom{margin-left:8px;display:inline-flex;gap:4px}
.cs-bar2{font-size:.82rem}
.cs-hint{color:var(--ink-3);font-size:.76rem}
.cs-err{background:color-mix(in srgb,var(--bad) 10%,var(--card));border:1px solid color-mix(in srgb,var(--bad) 40%,var(--rule));border-radius:8px;padding:6px 10px;font-size:.86rem}
.cs-views{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(min(100%,420px),1fr))}
.cs-plot{margin:0;border:1px solid var(--rule);border-radius:10px;padding:8px 8px 4px;background:var(--paper);min-width:0}
.cs-plot figcaption{font-size:.78rem;color:var(--ink-3);margin-bottom:2px}
.cs-svg{width:100%;height:auto;display:block;touch-action:pan-y;user-select:none}
.cs-p-rl .cs-svg{touch-action:none;cursor:crosshair}
.cs-p-bode{grid-column:auto}
.cs-box{fill:none;stroke:var(--ink-3);stroke-width:1}
.cs-gr{fill:none;stroke:var(--rule);stroke-width:1}
.cs-gr.minor{stroke-width:.6;opacity:.6}
.cs-axl{fill:none;stroke:var(--ink-3);stroke-width:1.3}
.cs-tk{font:500 10.5px var(--mono);fill:var(--ink-3)}
.cs-ax-t{font:600 11px var(--mono);fill:var(--ink-2)}
.cs-hv-t{font:500 11px var(--mono);fill:var(--ink-2)}
.cs-br{fill:none;stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.cs-br.neg{stroke-dasharray:6 3}
.cs-pz path{fill:none;stroke:var(--ink);stroke-width:2.4;stroke-linecap:round}
.cs-pz circle:not(.cs-hit){fill:var(--paper);stroke:var(--ink);stroke-width:2.2}
.cs-hit{fill:transparent;stroke:none;cursor:grab}
.cs-pz:hover path,.cs-pz:hover circle:not(.cs-hit){stroke:var(--accent)}
.cs-delmode .cs-pz{cursor:not-allowed}
.cs-clp{fill:var(--accent);stroke:var(--paper);stroke-width:1.5}
.cs-asy{fill:none;stroke:var(--ink-3);stroke-width:1.4;stroke-dasharray:6 4}
.cs-cen{fill:var(--ink-3)}
.cs-brk{fill:var(--b3);stroke:var(--paper);stroke-width:1.2}
.cs-crs{fill:var(--bad);stroke:var(--paper);stroke-width:1}
.cs-zl{fill:none;stroke:var(--b4);stroke-width:1;stroke-dasharray:2 4;opacity:.8}
.cs-zt{font:500 10px var(--mono);fill:var(--b4)}
.cs-cv{fill:none;stroke:var(--b1);stroke-width:2.4;stroke-linejoin:round;stroke-linecap:round}
.cs-cv.neg{stroke:var(--b1);stroke-dasharray:3 4;opacity:.55;stroke-width:1.8}
.cs-zero{fill:none;stroke:var(--ink-3);stroke-width:1.2}
.cs-m180{stroke:var(--bad);stroke-dasharray:5 4;opacity:.75}
.cs-cor{stroke:var(--rule);stroke-width:1;stroke-dasharray:2 3}
.cs-mk{fill:none;stroke:var(--b3);stroke-width:1.8;stroke-dasharray:5 3}
.cs-mk2{fill:none;stroke:var(--b2);stroke-width:1.8;stroke-dasharray:5 3}
.cs-pm{fill:none;stroke:var(--b3);stroke-width:3}
.cs-band{fill:color-mix(in srgb,var(--b3) 14%,transparent);stroke:none}
.cs-uc{fill:none;stroke:var(--b4);stroke-width:1.1;stroke-dasharray:3 3;opacity:.8}
.cs-m1{fill:none;stroke:var(--bad);stroke-width:2.6;stroke-linecap:round}
.cs-arr{stroke:var(--b1);fill:none}
.cs-arh{fill:var(--b1)}
.cs-nytxt{font:600 11.5px var(--mono);fill:var(--ink)}
.cs-hv{stroke:var(--ink-3);stroke-width:1;fill:none}
.cs-hd{fill:var(--accent);stroke:var(--paper);stroke-width:1.5}
.cs-hover{min-height:1.2em;font-size:.76rem;color:var(--ink-2);padding:2px 4px}
.cs-hide-ans .cs-ans{display:none}
.cs-read{display:flex;flex-wrap:wrap;gap:6px 10px}
.cs-rd{display:inline-flex;align-items:baseline;gap:6px;background:var(--paper);border:1px solid var(--rule);border-radius:8px;padding:4px 10px;font-size:.88rem}
.cs-rd .mono{color:var(--ink-3);font-size:.72rem}
.cs-rd-w{flex:1 1 100%}
.cs-pol{font-family:var(--mono);font-size:.82rem;margin-right:8px;white-space:nowrap}
.cs-pol i{font-style:normal;color:var(--ink-3);font-size:.72rem}
.cs-ok{color:var(--ok)}.cs-bad{color:var(--bad)}.cs-warn{color:var(--warnc)}
.cs-rules{border-top:1px dashed var(--rule);padding-top:10px}
.cs-rules-h{display:flex;flex-wrap:wrap;justify-content:space-between;gap:4px 12px;margin-bottom:6px}
.cs-rules-h .mono{color:var(--ink-3);font-size:.76rem}
.cs-rules dl{margin:0;display:grid;gap:6px}
.cs-rules dl > div{display:grid;gap:1px;padding:6px 10px;border-radius:8px;background:var(--paper);border:1px solid var(--rule)}
.cs-rules dt{font:600 .78rem var(--mono);color:var(--accent)}
.cs-rules dd{margin:0;font-size:.9rem;overflow-wrap:anywhere}
/* Routh calculator + PID lab (shared form look) */
.rh-calc,.pid-lab{margin:20px 0;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px;display:grid;gap:10px;min-width:0}
.rh-calc table{border-collapse:collapse;font-family:var(--mono);font-size:.92rem;margin:0}
.rh-calc td,.rh-calc th{border:1px solid var(--rule);padding:5px 12px;text-align:right}
.rh-calc th{background:var(--paper-2);color:var(--accent);font-weight:600;text-align:center}
.rh-calc td.neg{color:var(--bad);font-weight:600}
.rh-calc td.eps{color:var(--warnc)}
.rh-calc .rh-out{font-size:.92rem}
.rh-calc .rh-steps{font-size:.88rem;color:var(--ink-2)}
.pid-lab .pid-grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr))}
.pid-lab label.sl{display:grid;grid-template-columns:3.2rem 1fr 4.5rem;gap:8px;align-items:center;font-size:.88rem}
.pid-lab label.sl .mono{color:var(--accent);font-weight:600}
.pid-lab input[type=range]{accent-color:var(--accent);min-width:0}
.pid-lab output{font-family:var(--mono);font-size:.82rem;text-align:right}
/* block diagrams / computed figures on control pages */
.csfig{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px;margin:16px 0;color:var(--ink)}
.csfig svg{width:100%;max-width:680px;height:auto;margin:0 auto;display:block}
.csfig figcaption{font-size:.84rem;color:var(--ink-3);text-align:center;margin-top:8px}
.csfig .ax{stroke:var(--ink-3);stroke-width:1.2;fill:none}
.csfig .gr{stroke:var(--rule);stroke-width:1;fill:none}
.csfig .tk{font:500 10.5px var(--mono);fill:var(--ink-3)}
.csfig .lb{font:600 12px var(--mono);fill:var(--ink-2)}
.csfig .lbk{font:600 12px var(--mono);fill:var(--accent)}
.csfig .c1{fill:none;stroke:var(--b1);stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.csfig .c2{fill:none;stroke:var(--b2);stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.csfig .c3{fill:none;stroke:var(--b3);stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.csfig .c4{fill:none;stroke:var(--b4);stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.csfig .dsh{fill:none;stroke:var(--ink-3);stroke-width:1.3;stroke-dasharray:6 4}
.csfig .thin{fill:none;stroke:var(--ink-3);stroke-width:1}
.csfig .blk{fill:var(--paper);stroke:var(--ink);stroke-width:1.6}
.csfig .sum{fill:var(--paper);stroke:var(--ink);stroke-width:1.6}
.csfig .wire{fill:none;stroke:var(--ink);stroke-width:1.6;stroke-linejoin:round}
.csfig .arh{fill:var(--ink)}
.csfig .px{fill:none;stroke:var(--ink);stroke-width:2.2;stroke-linecap:round}
.csfig .zo{fill:var(--paper);stroke:var(--ink);stroke-width:2}
.csfig .mkr{fill:var(--bad);stroke:var(--paper);stroke-width:1}
.csfig .mkg{fill:var(--b3);stroke:var(--paper);stroke-width:1}
.csfig .shade{fill:color-mix(in srgb,var(--bad) 8%,transparent);stroke:none}
.csfig .shadeg{fill:color-mix(in srgb,var(--b3) 10%,transparent);stroke:none}
@media (max-width:560px){.cs-lab{padding:10px}.cs-views{grid-template-columns:minmax(0,1fr)}.cs-rd{font-size:.82rem}}
@media print{.cs-lab .cs-bar,.cs-lab .cs-bar2{display:none}}
/* static Routh tables in lessons */
.rt-wrap{overflow-x:auto;margin:10px 0}
table.rt{border-collapse:collapse;font-family:var(--mono);font-size:.92rem;width:auto;margin:0}
table.rt th,table.rt td{border:none;border-bottom:1px solid var(--rule);padding:4px 14px;text-align:center;white-space:nowrap}
table.rt th{color:var(--ink-3);font-weight:500;border-right:1.5px solid var(--ink-3);text-align:left}
table.rt td:nth-child(2){background:color-mix(in srgb,var(--accent) 9%,transparent);font-weight:600}
table.rt td.neg{color:var(--bad)}
table.rt td.eps,table.rt tr.aux td{color:var(--warnc)}
table.rt caption{caption-side:bottom;font:500 .78rem var(--sans);color:var(--ink-3);padding-top:6px;text-align:left}
.rh-tab td:first-of-type{font-weight:600}
.rh-calc table{width:auto;min-width:min(100%,420px)}
.cs-gal-search{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center;margin:18px 0 0;padding:12px 14px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.cs-gal-search input{flex:1 1 240px;min-width:0;font:inherit;font-size:.95rem;padding:8px 12px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.cs-gal-search .mono{color:var(--ink-3);font-size:.82rem}
table.cs-gal td{font-size:.9rem;vertical-align:top}
table.cs-gal td:last-child{white-space:nowrap}
.path-links{margin:18px 0 0;font-size:.92rem;color:var(--ink-2)}
.lab-card .csfig.lab-fig svg{background:var(--paper)}
.cs-page .katex-display{overflow-x:auto;overflow-y:hidden;padding-bottom:2px}
.cs-page pre{overflow-x:auto;max-width:100%}
.cs-bar > .cs-f{max-width:100%;min-width:0}
.cs-pre{min-width:0;max-width:100%;text-overflow:ellipsis}
.cs-f-tf{flex:1 1 220px}
.pid-lab > *,.cs-lab > *,.rh-calc > *{min-width:0}
.cs-tf{width:100%}
/* ==========================================================================
FOURIER SERIES & HARMONIC LAB (/learn/fourier-series/) — assets/fs-core.js + fs-lab.js
========================================================================== */
.fs-lab{--c1:#f6d32d;--c2:#2ed3e6;--cm:#ff6bd6;--lcd:#0c1b24;margin:20px 0;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px;display:grid;gap:12px;min-width:0}
.fs-lab:not(.fsl-ready){min-height:320px}
.fs-lab > *{min-width:0}
.fs-lab noscript{display:block;padding:12px;color:var(--ink-3)}
.fsl-bar{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center;justify-content:space-between}
.fsl-tabs{display:flex;gap:6px;overflow-x:auto;padding-bottom:2px;scrollbar-width:thin;max-width:100%}
.fsl-tabs button{flex:none;font:600 .86rem var(--sans);padding:7px 14px;border-radius:999px;border:1px solid var(--rule);background:var(--paper);color:var(--ink-2);cursor:pointer;white-space:nowrap}
.fsl-tabs button[aria-selected="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.fsl-tools{display:flex;flex-wrap:wrap;gap:6px;align-items:center;min-width:0}
.fsl-pre{font:inherit;font-size:.88rem;padding:7px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);max-width:100%;min-width:0}
.fsl-btn{font:600 .8rem var(--sans);padding:7px 12px;border-radius:999px;border:1px solid var(--rule);background:var(--paper);color:var(--signal);cursor:pointer;text-decoration:none;white-space:nowrap}
.fsl-btn:hover{border-color:var(--signal)}
.fsl-pane{display:grid;gap:12px;min-width:0}
.fsl-pane > *{min-width:0}
.fsl-ctl{display:grid;gap:8px;padding:10px 12px;border:1px solid var(--rule);border-radius:12px;background:var(--paper)}
.fsl-row{display:flex;flex-wrap:wrap;gap:8px 18px;align-items:center;min-width:0}
.fsl-row[hidden]{display:none}
.fsl-f{display:inline-flex;align-items:center;gap:8px;font-size:.88rem;min-width:0;max-width:100%}
.fsl-f select,.fsl-f input{font:inherit;font-size:.9rem;padding:6px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--card);color:var(--ink);min-width:0;max-width:100%}
.fsl-f input{font-family:var(--mono)}
.fsl-wsel{flex:1 1 300px}.fsl-wsel select{flex:1}
.fsl-tnum input{width:96px}
.fsl-expr{flex:1 1 320px}.fsl-expr input{flex:1;width:100%}
.fsl-l{color:var(--ink-3);font-size:.8rem;white-space:nowrap}
.fsl-sl{display:grid;grid-template-columns:minmax(0,auto) minmax(90px,1fr) auto;gap:8px;align-items:center;font-size:.86rem;flex:1 1 260px;min-width:0}
.fsl-sl .fsl-l{white-space:normal}
.fsl-sl input[type=range]{width:100%;min-width:0;accent-color:var(--accent)}
.fsl-sl output{font:600 .8rem var(--mono);min-width:4.5em;text-align:right;color:var(--ink)}
.fsl-chk{display:inline-flex;align-items:center;gap:6px;font-size:.86rem;color:var(--ink-2);cursor:pointer}
.fsl-chk input{accent-color:var(--accent);width:16px;height:16px}
.fsl-hint{font-size:.76rem;color:var(--ink-3);flex:1 1 100%}
.fsl-nrow .fsl-sl{flex:1 1 320px}
.fsl-more{border-top:1px dashed var(--rule);padding-top:6px}
.fsl-more > summary{cursor:pointer;font-size:.86rem;font-weight:600;color:var(--signal);padding:2px 0}
.fsl-more > .fsl-row{margin-top:8px}
.fsl-views{display:grid;gap:12px;grid-template-columns:minmax(0,1fr)}
@media (min-width:1080px){.lab-page .fsl-views{grid-template-columns:repeat(2,minmax(0,1fr))}}
.fsl-plot{margin:0;border:1px solid var(--rule);border-radius:10px;padding:8px 8px 4px;background:var(--paper);min-width:0;position:relative}
.fsl-plot figcaption{display:flex;flex-wrap:wrap;gap:4px 10px;align-items:center;font-size:.78rem;color:var(--ink-3);margin:0 2px 4px}
.fsl-plot figcaption b{color:var(--ink-2)}
.fsl-svg{width:100%;height:auto;display:block}
.fsl-svg.fsl-hidden{filter:blur(9px);opacity:.5;pointer-events:none}
.fsl-reveal{position:absolute;left:50%;top:55%;transform:translate(-50%,-50%);font:600 .9rem var(--sans);padding:9px 16px;border-radius:999px;border:1.5px solid var(--ink);background:var(--card);color:var(--ink);cursor:pointer}
.fsl-seg{display:inline-flex;border:1px solid var(--rule);border-radius:999px;overflow:hidden;margin-left:auto}
.fsl-seg button{font:500 .74rem var(--sans);padding:3px 10px;border:0;background:var(--card);color:var(--ink-2);cursor:pointer}
.fsl-seg button + button{border-left:1px solid var(--rule)}
.fsl-seg button[aria-pressed="true"]{background:var(--ink);color:var(--paper)}
.fsl-key{display:inline-flex;align-items:center;gap:5px}
.fsl-key::before{content:"";width:18px;height:0;border-top:2.5px solid currentColor}
.fsl-key.k-orig{color:var(--ink-2)}.fsl-key.k-orig::before{border-top-style:dashed}
.fsl-key.k-sum{color:var(--accent)}.fsl-key.k-comp{color:var(--b1)}.fsl-key.k-in{color:#b39400}
.fsl-key.k-lim{color:var(--bad)}.fsl-key.k-lim::before{border-top-width:2px}
.fsl-key.k-over{color:var(--bad)}.fsl-key.k-over::before{border-top-width:9px;width:10px}
.fsl-box{fill:none;stroke:var(--ink-3);stroke-width:1}
.fsl-gr{stroke:var(--rule);stroke-width:1}
.fsl-zero{stroke:var(--ink-3);stroke-width:1.2}
.fsl-tk{font:500 10.5px var(--mono);fill:var(--ink-3)}
.fsl-axl{font:600 11px var(--mono);fill:var(--ink-2)}
.fsl-orig{fill:none;stroke:var(--ink-2);stroke-width:1.6;stroke-dasharray:6 4}
.fsl-sum{fill:none;stroke:var(--accent);stroke-width:2.4;stroke-linejoin:round}
.fsl-in{fill:none;stroke:#d9a400;stroke-width:1.8}
.fsl-err{fill:none;stroke:var(--bad);stroke-width:1.2;opacity:.8}
.fsl-cmp{fill:none;stroke-width:1.4;opacity:.85}
.fsl-cmp.c0{stroke:var(--b1)}.fsl-cmp.c1{stroke:var(--b3)}.fsl-cmp.c2{stroke:var(--b4)}.fsl-cmp.c3{stroke:var(--b5)}.fsl-cmp.c4{stroke:var(--b6)}
.fsl-ctag{font:600 10.5px var(--mono)}
.fsl-ctag.c0{fill:var(--b1)}.fsl-ctag.c1{fill:var(--b3)}.fsl-ctag.c2{fill:var(--b4)}.fsl-ctag.c3{fill:var(--b5)}.fsl-ctag.c4{fill:var(--b6)}
.fsl-b{fill:var(--signal)}
.fsl-b.off{fill:color-mix(in srgb,var(--signal) 22%,var(--paper))}
.fsl-b.dc{fill:var(--b4)}
.fsl-b.in{fill:#d9a400;opacity:.75}
.fsl-b.fsl-ph{fill:var(--b3)}.fsl-b.fsl-ph.off{fill:color-mix(in srgb,var(--b3) 25%,var(--paper))}
.fsl-zbar{fill:var(--ink-3);opacity:.5}
.fsl-hline{fill:none;stroke:var(--ink-2);stroke-width:1.4;stroke-dasharray:4 3}
.fsl-b.fund{fill:var(--ink-3)}
.fsl-b.seqp{fill:var(--b1)}.fsl-b.seqn{fill:var(--b2)}.fsl-b.seq0{fill:var(--b4)}
.fsl-b.over{fill:var(--bad)}
.fsl-lim{fill:none;stroke:var(--bad);stroke-width:2}
.fsl-read{display:grid;gap:8px}
.fsl-badges{display:flex;flex-wrap:wrap;gap:6px}
.fsl-badge{font-size:.8rem;padding:3px 10px;border-radius:999px;background:color-mix(in srgb,var(--b3) 12%,var(--card));border:1px solid color-mix(in srgb,var(--b3) 35%,var(--rule))}
.fsl-rds{display:flex;flex-wrap:wrap;gap:6px 8px}
.fsl-rd{display:inline-flex;align-items:baseline;gap:6px;background:var(--paper);border:1px solid var(--rule);border-radius:8px;padding:4px 10px;font-size:.86rem}
.fsl-rd i{font-style:normal;color:var(--ink-3);font-size:.74rem}
.fsl-rd b{font-family:var(--mono);font-weight:600;font-size:.84rem}
.fsl-err-msg{margin:0;padding:6px 10px;border-radius:8px;background:color-mix(in srgb,var(--bad) 10%,var(--card));border:1px solid color-mix(in srgb,var(--bad) 40%,var(--rule));font-size:.88rem}
.fsl-steps{border:1px solid var(--rule);border-radius:12px;background:var(--paper);padding:0}
.fsl-steps > summary{cursor:pointer;padding:10px 14px;font-weight:600;font-size:.92rem;color:var(--ink)}
.fsl-steps > summary::marker{color:var(--accent)}
.fsl-steps-b{padding:0 14px 12px;font-size:.9rem}
.lesson .fsl-ol{margin:0;padding-left:20px}
.lesson .fsl-ol > li{margin-bottom:8px}
.fsl-ol ul{margin:4px 0 0;padding-left:18px}
.fsl-ol a{color:var(--signal);font-family:var(--mono);font-size:.8rem}
.fsl-tw{overflow-x:auto;margin:6px 0}
table.fsl-tab{border-collapse:collapse;font-size:.82rem;min-width:100%;background:var(--card)}
table.fsl-tab th,table.fsl-tab td{padding:4px 9px;border-bottom:1px solid var(--rule);text-align:right;white-space:nowrap;font-family:var(--mono)}
table.fsl-tab th{font:500 .7rem var(--mono);color:var(--ink-3);background:var(--paper-2);text-align:right}
table.fsl-tab tr.off td{opacity:.45}
table.fsl-tab td:first-child,table.fsl-tab th:first-child{text-align:center}
/* power view: scope + analyzer */
.fsl-dash{display:grid;gap:12px;grid-template-columns:minmax(0,1fr)}
@media (min-width:1080px){.lab-page .fsl-dash{grid-template-columns:minmax(0,1.25fr) minmax(0,1fr)}}
.fsl-inst{background:color-mix(in srgb,var(--card) 70%,var(--paper-2));border:1px solid var(--rule);border-radius:14px;padding:10px;box-shadow:var(--shadow);min-width:0;display:grid;gap:8px;align-content:start}
.fsl-inst-h{display:flex;justify-content:space-between;align-items:baseline;gap:8px;flex-wrap:wrap;margin:0 2px}
.fsl-inst-h b{font:600 .8rem var(--mono);letter-spacing:.08em}
.fsl-inst-h .mono{color:var(--ink-3);font-size:.7rem}
.fsl-scope{width:100%;height:auto;display:block;border-radius:10px;border:3px solid #1b232b}
.fsl-scr{fill:#0b1014}
.fsl-sg{stroke:rgba(200,210,220,.17);stroke-width:1;stroke-dasharray:1 4}
.fsl-sgc{stroke:rgba(200,210,220,.35);stroke-width:1}
.fsl-t1{fill:none;stroke:var(--c1);stroke-width:2.2;stroke-linejoin:round}
.fsl-t2{fill:none;stroke:var(--c2);stroke-width:2.2;stroke-linejoin:round}
.fsl-t2f{fill:none;stroke:var(--c2);stroke-width:1.6;stroke-dasharray:6 5;opacity:.75}
.fsl-tm{fill:none;stroke:var(--cm);stroke-width:1.6;opacity:.9}
.fsl-st{font:600 13px var(--mono);fill:#e6edf3}
.fsl-st.c1{fill:var(--c1)}.fsl-st.c2{fill:var(--c2)}.fsl-st.cm{fill:var(--cm)}
.fsl-scope-txt{font-size:.72rem;color:var(--ink-3)}
.fsl-scope-txt .c1{color:#b39400}.fsl-scope-txt .c2{color:#0e8fa0}
.fsl-scope-ctl{gap:6px 14px}
.fsl-nums{display:grid;gap:6px;grid-template-columns:repeat(auto-fill,minmax(min(100%,128px),1fr))}
.fsl-num{background:var(--lcd);border-radius:8px;padding:6px 10px;border-left:4px solid #2f4554;display:grid;gap:0}
.fsl-num i{font:500 .68rem var(--mono);font-style:normal;color:#7fb7c9;letter-spacing:.02em}
.fsl-num b{font:600 1.02rem/1.35 var(--mono);color:#e6f6ff;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.fsl-num.ok{border-left-color:#3fb950}.fsl-num.warn{border-left-color:#e3a008}.fsl-num.bad{border-left-color:#f85149}
.fsl-num.bad b{color:#ffb3ad}
.fsl-diag{display:grid;gap:6px}
.lesson .fsl-dh{margin:0 0 2px;font:600 .92rem var(--sans)}
.fsl-msg{display:grid;gap:2px;padding:8px 12px;border-radius:10px;border:1px solid var(--rule);border-left-width:4px;background:var(--paper);font-size:.88rem}
.fsl-msg b{font-weight:600}
.fsl-msg span{color:var(--ink-2)}
.fsl-msg a{color:var(--signal)}
.fsl-msg.ok{border-left-color:var(--ok)}.fsl-msg.warn{border-left-color:var(--warnc)}.fsl-msg.bad{border-left-color:var(--bad);background:color-mix(in srgb,var(--bad) 5%,var(--paper))}
@media (max-width:560px){.fs-lab{padding:10px}.fsl-sl{grid-template-columns:1fr auto;flex-basis:100%}.fsl-sl input[type=range]{grid-column:1/-1;grid-row:2}.fsl-sl output{grid-row:1;grid-column:2}.fsl-wsel{flex-basis:100%}.fsl-f{flex-wrap:wrap}.fsl-tools{width:100%}.fsl-pre{flex:1}.fsl-seg{margin-left:0}}
@media print{.fs-lab .fsl-ctl,.fs-lab .fsl-bar{display:none}}
/* lesson figures for the Fourier series */
.fsfig{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px;margin:16px 0;color:var(--ink)}
.fsfig svg{width:100%;max-width:680px;height:auto;margin:0 auto;display:block}
.fsfig figcaption{font-size:.84rem;color:var(--ink-3);text-align:center;margin-top:8px}
.fsfig .ax{stroke:var(--ink-3);stroke-width:1.2;fill:none}
.fsfig .gr{stroke:var(--rule);stroke-width:1;fill:none}
.fsfig .tk{font:500 11px var(--mono);fill:var(--ink-3)}
.fsfig .lb{font:600 12.5px var(--mono);fill:var(--ink-2)}
.fsfig .lba{font:600 12.5px var(--mono);fill:var(--accent)}
.fsfig .th{font:500 13px var(--sans);fill:var(--ink-2)}
.fsfig .w0{fill:none;stroke:var(--ink-2);stroke-width:1.6;stroke-dasharray:6 4}
.fsfig .w1{fill:none;stroke:var(--accent);stroke-width:2.4;stroke-linejoin:round;stroke-linecap:round}
.fsfig .w2{fill:none;stroke:var(--b1);stroke-width:2;stroke-linejoin:round}
.fsfig .w3{fill:none;stroke:var(--b3);stroke-width:2;stroke-linejoin:round}
.fsfig .w4{fill:none;stroke:var(--b4);stroke-width:2;stroke-linejoin:round}
.fsfig .w5{fill:none;stroke:var(--b5);stroke-width:2;stroke-linejoin:round}
.fsfig .bar{fill:var(--signal)}
.fsfig .bar2{fill:var(--accent)}
.fsfig .bar0{fill:var(--b4)}
.fsfig .barg{fill:color-mix(in srgb,var(--signal) 25%,var(--paper))}
.fsfig .dsh{fill:none;stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:5 4}
.fsfig .env{fill:none;stroke:var(--bad);stroke-width:1.6;stroke-dasharray:6 4}
.fsfig .fill1{fill:color-mix(in srgb,var(--accent) 16%,transparent)}
.fsfig .fill2{fill:color-mix(in srgb,var(--signal) 14%,transparent)}
.fsfig .blk{fill:var(--paper);stroke:var(--ink);stroke-width:1.6}
.fsfig .wire{fill:none;stroke:var(--ink);stroke-width:1.6;stroke-linejoin:round;stroke-linecap:round}
.fsfig .arh{fill:var(--ink)}
.fsfig .dot{fill:var(--accent);stroke:var(--card);stroke-width:1.5}
.fsfig .w6{fill:none;stroke:var(--bad);stroke-width:2.2;stroke-linejoin:round}
/* waveform thumbnails inside formula cards (waveform-table) */
.tf .wtfig{margin:4px 0 8px}
.tf .wtfig svg{width:100%;max-width:300px;height:auto;display:block}
.wtfig .ax{stroke:var(--ink-3);stroke-width:1;fill:none}
.wtfig .gr{stroke:var(--rule);stroke-width:1;fill:none}
.wtfig .w0{fill:none;stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:4 3}
.wtfig .w1{fill:none;stroke:var(--accent);stroke-width:2.2;stroke-linejoin:round;stroke-linecap:round}
.wtfig .arh{fill:var(--ink)}
.lab-card .fsfig.lab-fig svg{background:var(--paper)}
@media (max-width:1899px){.nav-links a.nav-sub{white-space:normal}}
/* ==========================================================================
POWER ELECTRONICS CONVERTER LAB (/learn/power-electronics/) — assets/pe-sim.js + pe-lab.js
========================================================================== */
.pe-lab{margin:20px 0;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px;display:grid;gap:10px;min-width:0}
.pe-lab:not(.pel-ready){min-height:320px}
.pe-lab > *{min-width:0}
.pe-lab noscript{display:block;padding:12px;color:var(--ink-3)}
.pe-top,.pe-row{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:flex-end}
.pe-f{display:flex;align-items:center;gap:6px;font-size:.86rem;margin:3px 0;min-width:0}
.pe-f > span{min-width:92px;color:var(--ink-2)}
.pe-top .pe-f > span,.pe-row .pe-f > span{min-width:0;font-family:var(--mono);font-size:.76rem}
.pe-f input[type=number],.pe-f select{flex:1;min-width:0;max-width:100%;font:500 .86rem var(--sans);padding:4px 7px;border-radius:7px;border:1px solid var(--rule);background:var(--paper);color:var(--ink)}
.pe-f em{font-style:normal;font-family:var(--mono);font-size:.72rem;color:var(--ink-3);min-width:38px}
.pe-c1{color:#b89a00}.pe-c2{color:#0e93a3}
.pe-schem{width:100%;max-width:520px;height:auto;margin:0 auto;display:block;color:var(--ink);fill:none;stroke:currentColor;stroke-width:2}
.pe-schem text{fill:currentColor;stroke:none;font:12px var(--mono)}
.pe-scope-wrap{position:relative}
.pe-scope{width:100%;height:auto;display:block;border-radius:10px;border:2px solid #2a4a5a;background:#0c1b24}
.pe-busy{position:absolute;right:10px;top:8px;font:12px var(--mono);color:#9fc;background:rgba(0,0,0,.5);padding:2px 8px;border-radius:6px}
.pe-meas{font-size:.86rem;line-height:1.75;padding:8px 12px;border-radius:10px;background:var(--paper-2)}
.pe-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:10px}
.pe-grid fieldset{border:1px solid var(--rule);border-radius:10px;padding:8px 10px;margin:0;min-width:0}
.pe-grid legend{font:700 .9rem var(--sans);padding:0 4px}
.pe-des{grid-column:1/-1}
.pe-calc{font-size:.86rem;line-height:1.75;margin:6px 0}
.pe-note{font-size:.78rem;color:var(--ink-3);margin:4px 0 0}
.pe-warn{color:var(--accent);font-weight:600}
@media (max-width:560px){.pe-f > span{min-width:80px}}
.lesson pre.code code{background:none;color:inherit;padding:0;font:inherit;white-space:inherit}
/* ==========================================================================
SOLAR PV DESIGN (/learn/solar-pv/) — assets/pv-calc.js
========================================================================== */
.pv-calc{border-left-color:#d99a12}
.pv-calc .fc-out,.pv-iv .fc-out{background:color-mix(in srgb,#d99a12 9%,transparent)}
.pv-chk.ok{color:var(--ok)} .pv-chk.bad{color:var(--red,#c0392b)}
.pv-fig{margin:10px 0 0;min-width:0}
.pv-fig:empty{display:none}
.pv-svg{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.pv-svg .gr{stroke:var(--rule);stroke-width:1}
.pv-svg .ax{stroke:var(--ink-3);stroke-width:1.2}
.pv-svg .tk{font:11px var(--mono);fill:var(--ink-3)}
.pv-svg .al{font:12px var(--sans);fill:var(--ink-2)}
.pv-svg .al.c1,.pv-svg .tk.c1{fill:var(--signal)} .pv-svg .al.c2,.pv-svg .tk.t2{fill:var(--accent)}
.pv-svg .w1{fill:none;stroke:var(--signal);stroke-width:2.4;stroke-linejoin:round}
.pv-svg .w2{fill:none;stroke:var(--accent);stroke-width:2.4;stroke-linejoin:round}
.pv-svg .bar{fill:#d99a12}
.pv-svg .dot{fill:var(--accent);stroke:var(--card);stroke-width:2}
.pv-svg .dot2{fill:var(--ink-3);stroke:var(--card);stroke-width:2}
.pv-svg .ml{font:600 12px var(--sans);fill:var(--ink)}
.pv-note{margin:8px 0 0;font-size:.84rem;color:var(--ink-3)}
.pv-iv{border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px 16px;margin:20px 0;min-width:0}
.lesson .pv-iv .fc-t{margin:0 0 8px;display:flex;flex-wrap:wrap;gap:4px 10px;align-items:baseline}
.pv-iv .fc-t .mono{color:var(--ink-3);font-size:.74rem}
.pv-ctl{display:grid;gap:8px 14px;grid-template-columns:repeat(auto-fill,minmax(min(100%,200px),1fr));font-size:.86rem;color:var(--ink-2)}
.pv-ctl label{display:grid;grid-template-columns:1fr auto;gap:2px 8px;align-items:center}
.pv-ctl output{font:600 .82rem var(--mono);color:var(--ink)}
.pv-ctl input[type=range]{grid-column:1/-1;width:100%;accent-color:var(--accent)}
.pv-ctl label.pv-cb{display:flex;gap:6px;align-items:center}
.pv-btns{grid-column:1/-1;display:flex;flex-wrap:wrap;gap:6px}
.pv-flow{display:flex;flex-wrap:wrap;gap:6px;align-items:center;margin:14px 0;font-size:.88rem}
.pv-flow span{padding:6px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--card)}
.pv-flow i{font-style:normal;color:var(--ink-3)}
@media print{.pv-calc,.pv-iv{display:none!important}}
.pv-ws{border:1px solid var(--rule);border-radius:10px;background:var(--card);padding:10px 14px;margin:10px 0}
.pv-ws summary{cursor:pointer}
.pv-ws p{margin:8px 0 0}
/* ==========================================================================
NAV GROUPS (2026-10-13): the main menu is grouped — dropdowns on desktop (≥1900 px),
accordion sections inside the hamburger panel below that. Markup in src/layout.html:
========================================================================== */
.nav-grp{position:relative}
.nav-tg{font:inherit;background:none;border:0;color:var(--ink-2);cursor:pointer;padding:0;display:inline-flex;align-items:center;gap:7px;white-space:nowrap;text-align:left}
.nav-tg:hover{color:var(--ink)}
.nav-tg::after{content:"";flex:none;width:6px;height:6px;border-right:1.6px solid currentColor;border-bottom:1.6px solid currentColor;transform:translateY(-2px) rotate(45deg);transition:transform .18s}
.nav-grp[data-open] > .nav-tg::after{transform:translateY(1px) rotate(-135deg)}
.nav-grp.nav-cur > .nav-tg{color:var(--ink);font-weight:600}
.nav-list{display:none}
.nav-list .nav-h{display:block;font:500 .72rem var(--mono);letter-spacing:.02em;color:var(--ink-3);text-transform:uppercase}
@media (min-width:1900px){
.nav-grp{display:flex;align-items:center}
.nav-grp::after{content:"";position:absolute;left:-8px;right:-8px;top:100%;height:16px} /* hover bridge to the panel */
.nav-grp.nav-cur > .nav-tg{box-shadow:inset 0 -2px 0 var(--accent)}
.nav-list{position:absolute;top:calc(100% + 14px);left:-14px;z-index:40;min-width:250px;max-height:calc(100vh - 90px);overflow:auto;
background:var(--paper);border:1px solid var(--rule);border-radius:12px;box-shadow:0 18px 40px -18px rgba(0,0,0,.35);padding:8px;gap:1px}
.nav-list-r{left:auto;right:-14px}
.nav-list-wide{grid-template-columns:1fr 1fr;min-width:540px;column-gap:6px}
.nav-list-wide .nav-h{grid-column:1/-1}
.nav-grp:hover > .nav-list,.nav-grp:focus-within > .nav-list,.nav-grp[data-open] > .nav-list{display:grid}
.nav-links .nav-list a{padding:7px 10px;border-radius:7px;white-space:nowrap;font-size:.9rem;box-shadow:none}
.nav-links .nav-list a:hover{background:var(--paper-2)}
.nav-links .nav-list a[aria-current="page"]{background:color-mix(in srgb,var(--accent) 10%,transparent);color:var(--ink)}
.nav-list .nav-h{padding:10px 10px 3px}
}
@media (max-width:1899px){
.nav-grp{border-bottom:1px solid var(--rule)}
.nav-tg{display:flex;width:100%;justify-content:space-between;padding:15px 4px;font-size:1.08rem;color:var(--ink)}
.nav-tg::after{margin-right:6px}
.nav-grp.nav-cur > .nav-tg{color:var(--accent)}
.nav-grp[data-open] > .nav-list{display:flex;flex-direction:column;padding:0 0 10px 10px;border-left:2px solid var(--rule);margin:0 0 10px 6px}
.nav-links .nav-list a{padding:10px 8px;font-size:.98rem;border-bottom:0;color:var(--ink-2);white-space:normal}
.nav-links .nav-list a[aria-current="page"]{color:var(--accent);font-weight:600}
.nav-list .nav-h{padding:12px 8px 2px}
}
@media (min-width:1900px) and (max-width:2299px){.nav-tg{gap:5px}}
.nav-links .nav-list a.nav-here{color:var(--accent);font-weight:600}
/* ==========================================================================
VECTOR ALGEBRA LAB — /learn/vector-algebra/ · assets/vector-lab.js
========================================================================== */
.vec-lab{margin:22px 0;padding:16px;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);display:grid;gap:12px;min-width:0}
.vec-lab > *{min-width:0}
.vec-lab:not([data-vecl-ready]){min-height:280px}
.lesson .vec-lab p{margin:0}
.vec-lab .vecl-heading{font:600 1rem/1.5 var(--sans);color:var(--ink)}
.vecl-controls{display:flex;flex-wrap:wrap;gap:10px 14px;align-items:end}
.vecl-field{display:grid;gap:4px;font-size:.85rem;flex:1;min-width:min(100%,190px)}
.vecl-field > span{color:var(--ink-2)}
.vecl-field select,.vecl-number input{min-height:44px;width:100%;font:500 .87rem var(--sans);border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);padding:8px 10px}
.vecl-field select{max-width:100%}
.vecl-vectors{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.vecl-vector{display:flex;flex-wrap:wrap;gap:8px;border:1px solid var(--rule);border-radius:10px;margin:0;padding:10px 12px 12px;min-width:0}
.vecl-vector legend{padding:0 6px;font-size:.92rem;font-weight:600}
.vecl-vector-a{border-top:3px solid var(--accent)}
.vecl-vector-b{border-top:3px solid var(--signal)}
.vecl-vector-a legend{color:var(--accent)}
.vecl-vector-b legend{color:var(--signal)}
.vecl-number{display:grid;gap:4px;flex:1 1 65px;min-width:0;font:500 .82rem var(--mono);color:var(--ink-2)}
.vecl-number input{font-family:var(--mono);max-width:100%;min-width:0}
.vecl-number input[aria-invalid="true"]{border-color:var(--accent);outline:1px solid var(--accent)}
.vecl-controls > .vecl-number{max-width:180px;flex-basis:120px}
.vecl-note,.vecl-caption{font-size:.81rem;line-height:1.6;color:var(--ink-3)}
.vecl-presets{display:flex;flex-wrap:wrap;gap:6px}
.vecl-presets button{font:500 .8rem/1.4 var(--sans);text-align:left;min-height:44px;padding:7px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);cursor:pointer}
.vecl-presets button:hover{border-color:var(--accent);background:var(--paper-2)}
.vecl-checkbox{display:flex;align-items:center;gap:6px;font-size:.86rem;min-height:44px;cursor:pointer}
.vecl-checkbox input{width:18px;height:18px;accent-color:var(--accent)}
.vec-lab .vecl-error{border:1px solid var(--accent);border-radius:8px;padding:10px 12px;color:var(--accent);background:color-mix(in srgb,var(--accent) 7%,var(--paper));font-size:.9rem}
.vecl-figure{margin:0;min-width:0}
.vecl-plot{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.vecl-caption{margin-top:8px}
.vecl-grid{stroke:var(--rule);stroke-width:.8}
.vecl-axis{stroke:var(--ink-3);stroke-width:1.4;fill:var(--ink-3)}
.vecl-arrow{stroke-width:3;stroke-linecap:round}
.vecl-head{stroke:none}
.vecl-a{color:var(--accent);stroke:var(--accent);fill:var(--accent)}
.vecl-b{color:var(--signal);stroke:var(--signal);fill:var(--signal)}
.vecl-result{color:var(--ok);stroke:var(--ok);fill:var(--ok)}
.vecl-perp{color:var(--ink-2);stroke:var(--ink-2);fill:var(--ink-2)}
.vecl-dash{stroke-dasharray:7 5;stroke-width:2;opacity:.8}
.vecl-component{stroke:var(--accent);stroke-width:1.5;stroke-dasharray:4 5;opacity:.7}
.vecl-label{font:600 15px var(--sans);fill:var(--ink);stroke:none;paint-order:stroke;stroke-width:3px;stroke:var(--paper);stroke-linejoin:round}
.vecl-label.vecl-a{fill:var(--accent)}
.vecl-label.vecl-b{fill:var(--signal)}
.vecl-label.vecl-result{fill:var(--ok)}
.vecl-label.vecl-perp{fill:var(--ink-2)}
.vecl-tick{font:500 12px var(--mono);fill:var(--ink-3);stroke:none;paint-order:stroke;stroke-width:3px;stroke:var(--paper);stroke-linejoin:round}
.vecl-tick.vecl-a{fill:var(--accent)}
.vecl-right-angle,.vecl-angle{fill:none;stroke:var(--ink-2);stroke-width:1.5}
.vecl-legend{display:flex;flex-wrap:wrap;gap:4px 14px;font-size:.81rem;line-height:1.6}
.vecl-output{display:grid;gap:8px;font-size:.86rem;min-width:0}
.vecl-reading{display:grid;gap:3px;padding:8px 12px;border-radius:8px;background:var(--paper-2);overflow-wrap:anywhere}
.vecl-reading > b{font-size:.82rem;color:var(--ink-2)}
.vecl-reading > span{white-space:pre-wrap;line-height:1.7}
.vecl-answer{border-left:3px solid var(--ok);background:color-mix(in srgb,var(--ok) 8%,var(--paper))}
@media (max-width:560px){.vec-lab{padding:10px}.vecl-vectors{grid-template-columns:1fr}.vecl-vector{flex-wrap:nowrap}.vecl-field{flex-basis:100%}.vecl-label{font-size:24px}.vecl-tick{font-size:20px}.vecl-plot{min-height:220px}}
@media print{.vecl-controls,.vecl-vectors,.vecl-presets,.vecl-checkbox,.vecl-note{display:none!important}.vec-lab{break-inside:avoid}.vecl-output{font-size:9pt}}
/* END VECTOR ALGEBRA LAB */
/* ==========================================================================
EV CHARGING · POWER SYSTEMS · POWER FACTOR (2026-10-13) — assets/ee-kit.js, ev-calc.js, ps-calc.js, pf-lab.js
========================================================================== */
:root{--c1:#1f5fa8;--c2:#c94f18;--c3:#2f7d4f;--c4:#8a5cc2;--c5:#d99a12;--c6:#c0392b;--c7:#6b7785}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){--c1:#6aa6e8;--c2:#f07a3e;--c3:#5fbf86;--c4:#b48ef0;--c5:#f2c14e;--c6:#ef6f61;--c7:#9aa6b2}}
:root[data-theme="dark"]{--c1:#6aa6e8;--c2:#f07a3e;--c3:#5fbf86;--c4:#b48ef0;--c5:#f2c14e;--c6:#ef6f61;--c7:#9aa6b2}
.ev-calc{border-left-color:#2f9e8f}
.ps-calc{border-left-color:#8a5cc2}
.pf-calc{border-left-color:#c94f18}
.ev-calc .fc-out{background:color-mix(in srgb,#2f9e8f 9%,transparent)}
.ps-calc .fc-out{background:color-mix(in srgb,#8a5cc2 8%,transparent)}
.pf-calc .fc-out{background:color-mix(in srgb,#c94f18 7%,transparent)}
.fc-out dt.fc-sep{grid-column:1/-1;font:600 .78rem var(--mono);color:var(--ink);border-top:1px solid var(--rule);padding-top:6px;margin-top:2px}
.fc-out dt.fc-sep + dd{display:none}
.ee-warn{color:var(--c6);font-weight:600}
.ee-intro{margin:0 0 8px}
.ee-svg{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.ee-svg .gr{stroke:var(--rule);stroke-width:1}
.ee-svg .gr.gx{stroke-dasharray:2 4;opacity:.8}
.ee-svg .ax{stroke:var(--ink-3);stroke-width:1.2}
.ee-svg .tk{font:11px var(--mono);fill:var(--ink-3)}
.ee-svg .tk.xs{font-size:8px}
.ee-svg .tk.lgt{fill:var(--ink-2)}
.ee-svg .tk.c1,.ee-svg .ml.c1{fill:var(--c1)} .ee-svg .tk.c2,.ee-svg .ml.c2{fill:var(--c2)}
.ee-svg .al{font:12px var(--sans);fill:var(--ink-2)}
.ee-svg .ml{font:600 12px var(--sans);fill:var(--ink)}
.ee-svg .ml.sm{font-size:11px}
.ee-svg polyline,.ee-svg line.s1,.ee-svg line.s2,.ee-svg line.s3,.ee-svg line.s5,.ee-svg line.s6{fill:none;stroke-width:2;stroke-linejoin:round;stroke-linecap:round}
.ee-svg .thick{stroke-width:2.6}
.ee-svg .s1{stroke:var(--c1)} .ee-svg .s2{stroke:var(--c2)} .ee-svg .s3{stroke:var(--c3)} .ee-svg .s4{stroke:var(--c4)} .ee-svg .s5{stroke:var(--c5)} .ee-svg .s6{stroke:var(--c6)} .ee-svg .s7{stroke:var(--c7)}
.ee-svg .f1{fill:var(--c1)} .ee-svg .f2{fill:var(--c2)} .ee-svg .f3{fill:var(--c3)} .ee-svg .f4{fill:var(--c4)} .ee-svg .f5{fill:var(--c5)} .ee-svg .f6{fill:var(--c6)} .ee-svg .f7{fill:var(--c7)}
.ee-svg .dsh{stroke-dasharray:6 5} .ee-svg .dsh2{stroke-dasharray:7 4;stroke-width:2.2}
.ee-svg .hl{stroke:var(--ink-3);stroke-width:1.2;fill:none}
.ee-svg .hl.dsh{stroke-dasharray:5 4}
.ee-svg .hl.red{stroke:var(--c6);stroke-dasharray:6 4;stroke-width:1.5}
.ee-svg .ee-a1{fill:color-mix(in srgb,var(--c7) 45%,transparent)}
.ee-svg .ee-a2{fill:color-mix(in srgb,var(--c1) 40%,transparent)}
.ee-svg .ee-a3{fill:color-mix(in srgb,var(--c3) 50%,transparent)}
.ee-svg .ee-a4{fill:color-mix(in srgb,var(--c4) 40%,transparent)}
.ee-svg .ee-trip{fill:color-mix(in srgb,var(--c6) 12%,transparent)}
.ee-svg .dot{fill:var(--accent);stroke:var(--card);stroke-width:2}
.ee-svg .dot2{fill:var(--ink-3);stroke:var(--card);stroke-width:2}
.ee-svg .dot.red{fill:var(--c6)} .ee-svg .dot.ok{fill:var(--c3)}
.ev-cp,.ev-sim,.ps-tcc,.pf-sim,.pf-bank{border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px 16px;margin:20px 0;min-width:0}
.lesson .ev-cp .fc-t,.lesson .ev-sim .fc-t,.lesson .ps-tcc .fc-t,.lesson .pf-sim .fc-t,.lesson .pf-bank .fc-t{margin:0 0 8px;display:flex;flex-wrap:wrap;gap:4px 10px;align-items:baseline}
.ev-cp .fc-t .mono,.ev-sim .fc-t .mono,.ps-tcc .fc-t .mono,.pf-sim .fc-t .mono,.pf-bank .fc-t .mono{color:var(--ink-3);font-size:.74rem}
.ev-cp .pv-ctl select,.pf-sim select{font:500 .86rem var(--mono);padding:5px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink)}
.pv-btns button[aria-pressed="true"],.pf-pre button[aria-pressed="true"]{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 14%,var(--card))}
.pv-btns .mono{font-size:.76rem;color:var(--ink-3);align-self:center}
.ev-pre,.pf-pre{margin:0 0 10px}
.ev-sim-body{display:flex;flex-direction:column;gap:12px}
.ev-sim-in{order:2;display:grid;gap:6px;grid-template-columns:repeat(auto-fill,minmax(min(100%,300px),1fr));align-items:start;min-width:0}
.ev-grp{border:1px solid var(--rule);border-radius:10px;background:var(--paper);padding:6px 10px}
.ev-grp summary{cursor:pointer;font-weight:600;font-size:.92rem;padding:2px 0}
.ev-grp .fc-in{margin:8px 0 4px;grid-template-columns:repeat(auto-fill,minmax(min(100%,140px),1fr))}
.ev-cb{display:flex!important;gap:6px;align-items:center;grid-column:1/-1;font-size:.84rem}
.ev-cb input{width:auto!important}
.ev-sim-out{order:1;min-width:0}
.ev-sim-out .fc-out{margin-top:10px}
.ps-tcc-t table{font-size:.84rem}
.ps-tcc-t input,.ps-tcc-t select{font:500 .84rem var(--mono);padding:5px 7px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink);width:100%;min-width:70px}
.ps-tcc-t select{min-width:150px}
.ps-sw{display:inline-block;width:12px;height:4px;border-radius:2px;margin-right:6px;vertical-align:middle}
.ps-sw.s1{background:var(--c1)} .ps-sw.s2{background:var(--c2)} .ps-sw.s3{background:var(--c3)}
.ps-tcc .fc-in{margin:10px 0}
.ps-ph{max-width:680px}
/* power factor simulator */
.pf-body{display:grid;gap:14px;grid-template-columns:minmax(0,1fr)}
.pf-sim{container-type:inline-size}
@container (min-width:1000px){.pf-body{grid-template-columns:minmax(280px,340px) minmax(0,1fr)}}
.pf-ctl,.pf-out{min-width:0;display:flex;flex-direction:column;gap:10px}
.pf-loads{display:grid;gap:6px;grid-template-columns:repeat(auto-fill,minmax(min(100%,250px),1fr))}
.pf-load{display:grid;grid-template-columns:auto 1fr auto;gap:4px 10px;align-items:center;border:1px solid var(--rule);border-radius:10px;padding:8px 10px;background:var(--paper)}
.pf-load.on{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 7%,var(--paper))}
.pf-ic{font-size:1.3rem;line-height:1}
.pf-ln{display:flex;flex-direction:column;min-width:0;font-size:.86rem;line-height:1.35}
.pf-ln small{color:var(--ink-3);font-size:.76rem}
.pf-qty{display:flex;align-items:center;gap:4px}
.pf-qty output{font:600 .9rem var(--mono);min-width:1.4em;text-align:center}
.pf-b{width:30px;height:30px;border-radius:8px;border:1px solid var(--rule);background:var(--card);color:var(--ink);font:600 1rem var(--mono);cursor:pointer}
.pf-b:hover{border-color:var(--ink-3)}
.pf-sl{grid-column:1/-1;display:grid;grid-template-columns:1fr auto;gap:2px 8px;font-size:.8rem;color:var(--ink-2)}
.pf-sl output{font:600 .78rem var(--mono);color:var(--ink)}
.pf-sl input{grid-column:1/-1;width:100%;accent-color:var(--accent)}
.pf-cap{border:1px dashed var(--ink-3);border-radius:10px;padding:8px 10px}
.pf-h{margin:0 0 6px;display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center;font-size:.88rem}
.pf-h input{width:4.5em;font:500 .85rem var(--mono);padding:4px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink)}
.pf-steps{display:grid;grid-template-columns:repeat(6,1fr);gap:5px;margin:0 0 6px}
.pf-step{padding:9px 0;border-radius:8px;border:1px solid var(--rule);background:var(--paper);color:var(--ink-2);font:600 .82rem var(--mono);cursor:pointer}
.pf-step.on{background:var(--c3);border-color:var(--c3);color:#fff}
.pf-sys{grid-template-columns:repeat(auto-fill,minmax(min(100%,130px),1fr))}
.pf-meters{display:grid;gap:6px;grid-template-columns:repeat(auto-fill,minmax(112px,1fr))}
.pf-m{border:1px solid var(--rule);border-radius:9px;background:#10161c;color:#e8f2ec;padding:6px 9px;display:flex;flex-direction:column;min-width:0}
.pf-m span{font-size:.7rem;color:#9fb3a8}
.pf-m b{font:600 1.18rem var(--mono);color:#7cf0b1;letter-spacing:.02em}
.pf-m i{font:normal .7rem var(--mono);color:#9fb3a8}
.pf-m.pm-p b{color:#8fc2ff} .pf-m.pm-q b{color:#ffb38a} .pf-m.pm-bad b{color:#ff8a7a} .pf-m.pm-ok b{color:#7cf0b1}
.pf-dialbox{grid-row:span 2;border:1px solid var(--rule);border-radius:9px;background:var(--paper);display:flex;flex-direction:column;align-items:center;justify-content:center;padding:4px}
.pf-dialbox .mono{font-size:.74rem;color:var(--ink-2)}
.pf-dial{border:0!important;background:none!important;max-width:150px}
.pf-needle{stroke:var(--c6);stroke-width:2.5;stroke-linecap:round;transition:all .4s}
.pf-wave-h{display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center;justify-content:space-between;font-size:.92rem}
.pf-cb{display:inline-flex;gap:5px;align-items:center;font-size:.82rem;color:var(--ink-2)}
.pf-now{margin:0;font-size:.78rem;color:var(--ink-2);min-height:1.4em}
.pf-in{color:var(--c3);font-weight:600} .pf-back{color:var(--c6);font-weight:600}
.pf-pair{display:grid;gap:10px;grid-template-columns:repeat(auto-fit,minmax(min(100%,240px),1fr))}
.ee-svg .pf-ppos{fill:color-mix(in srgb,var(--c3) 22%,transparent)}
.ee-svg .pf-pneg{fill:color-mix(in srgb,var(--c6) 30%,transparent)}
.ee-svg .pf-cur{stroke:var(--ink);stroke-width:1.2;stroke-dasharray:3 3}
.ee-svg .pf-arc{fill:none;stroke:var(--c4);stroke-width:1.6}
.ee-svg .pf-dash{stroke:var(--ink-3);stroke-dasharray:3 3;stroke-width:1}
.pf-cable{margin-top:0!important}
.pf-explain{font-size:.9rem!important;color:var(--ink-2)!important;border-left:3px solid var(--accent);padding-left:10px}
/* virtual capacitor bank */
.pf-panel{display:grid;gap:10px;grid-template-columns:minmax(0,1fr);margin:10px 0}
@media (min-width:760px){.pf-panel{grid-template-columns:minmax(0,1.2fr) minmax(0,1fr);align-items:center}}
.pf-ctrl{background:#1c2a24;border-radius:12px;padding:10px 12px;color:#d9f5e6;border:3px solid #3c4a44;box-shadow:inset 0 0 0 1px #0007}
.pf-lcd{display:flex;align-items:baseline;gap:10px;background:#9fc8a4;color:#13261b;border-radius:6px;padding:6px 10px;font-family:var(--mono)}
.pf-lcd b{font-size:1.9rem;letter-spacing:.04em}
.pf-lcd small{font-weight:700}
.pf-lcd2{font-size:.76rem;margin:6px 0;color:#b9d8c7}
.pf-leds{display:flex;flex-wrap:wrap;gap:6px}
.pf-led{display:flex;flex-direction:column;align-items:center;font:600 .74rem var(--mono);color:#8aa596;min-width:34px}
.pf-led::before{content:"";width:14px;height:14px;border-radius:50%;background:#33433b;margin-bottom:2px;box-shadow:inset 0 0 0 1px #0006}
.pf-led.on{color:#e3ffe9}
.pf-led.on::before{background:#3ef07f;box-shadow:0 0 8px #3ef07f}
.pf-led small{font-size:.62rem;font-weight:400}
.pf-time{display:grid;grid-template-columns:1fr auto;gap:2px 8px;font-size:.86rem;color:var(--ink-2)}
.pf-time output{font:600 .84rem var(--mono);color:var(--ink)}
.pf-time input{grid-column:1/-1;width:100%;accent-color:var(--accent)}
.ee-flow{display:flex;flex-wrap:wrap;gap:6px;align-items:center;margin:14px 0;font-size:.88rem}
.ee-flow span{padding:6px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--card)}
.ee-flow i{font-style:normal;color:var(--ink-3)}
.ee-cards{display:grid;gap:10px;grid-template-columns:repeat(auto-fit,minmax(min(100%,230px),1fr));margin:14px 0}
.ee-card{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:12px 14px}
.ee-card h3{margin:0 0 4px;font-size:1rem}
.ee-card p{margin:4px 0 0;font-size:.9rem}
.ee-card .mono{font-size:.74rem;color:var(--ink-3)}
.ee-fig{margin:16px 0}
.ee-fig svg{width:100%;height:auto;display:block;max-width:760px;margin:0 auto}
.ee-fig figcaption{font-size:.84rem;color:var(--ink-3);text-align:center;margin-top:6px}
.ee-fig .bx{fill:var(--card);stroke:var(--ink-2);stroke-width:1.4}
.ee-fig .bx2{fill:color-mix(in srgb,var(--accent) 10%,var(--card));stroke:var(--accent);stroke-width:1.4}
.ee-fig .ln{stroke:var(--ink-2);stroke-width:1.6;fill:none}
.ee-fig .ln2{stroke:var(--accent);stroke-width:2.2;fill:none}
.ee-fig .ln3{stroke:var(--c1);stroke-width:2.2;fill:none}
.ee-fig .ln4{stroke:var(--c3);stroke-width:2.2;fill:none}
.ee-fig .lnd{stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:4 4;fill:none}
.ee-fig text{font:12px var(--sans);fill:var(--ink)}
.ee-fig .t2{font-size:10.5px;fill:var(--ink-3)}
.ee-fig .tb{font-weight:600}
.ee-fig .fa{fill:var(--accent)} .ee-fig .fc1{fill:var(--c1)} .ee-fig .fc3{fill:var(--c3)} .ee-fig .fi{fill:var(--ink-2)}
@media print{.ev-cp,.ev-sim,.ps-tcc,.pf-sim,.pf-bank,.ev-calc,.ps-calc,.pf-calc{display:none!important}}
.pf-sim[data-mini] .pf-body{display:flex;flex-direction:column}.pf-sim[data-mini] .pf-out{order:-1}.pf-sim[data-mini] .pf-explain{display:none}
/* ==========================================================================
VECTORS 2026-10-14 — 3D viewer / scenes / Vector Studio (assets/vec3d.js),
mechanics lab (vec-mech.js), field lab (vec-field.js), AC phasor lab (ac-phasor.js)
========================================================================== */
:root{--axx:#d23f3f;--axy:#2c9a55;--axz:#2f6fd6}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){--axx:#ff7a70;--axy:#5fd38b;--axz:#78a9ff}}
:root[data-theme="dark"]{--axx:#ff7a70;--axy:#5fd38b;--axz:#78a9ff}
.v3d,.v3d-studio,.mech-lab,.fld-lab,.ph-lab{border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px 16px;margin:22px 0;min-width:0;container-type:inline-size}
.v3d:not(.v3-ready),.v3d-studio:not(.v3-ready),.mech-lab:not(.mx-ready),.fld-lab:not(.fl-ready),.ph-lab:not(.ph-ready){min-height:320px}
.lesson .v3d p,.lesson .v3d-studio p,.lesson .mech-lab p,.lesson .fld-lab p,.lesson .ph-lab p{margin:0}
.v3-t{display:flex;flex-wrap:wrap;gap:2px 12px;align-items:baseline;justify-content:space-between;margin:0 0 10px!important}
.v3-t b{font:600 1rem/1.4 var(--sans)}
.v3-t .mono{color:var(--ink-3);font-size:.74rem}
.v3-body{display:grid;gap:14px;grid-template-columns:minmax(0,1fr)}
@container (min-width:860px){.v3-body{grid-template-columns:minmax(0,1.35fr) minmax(280px,1fr);align-items:start}}
.v3-fig{min-width:0;position:relative}
.v3-svg{width:100%;height:auto;display:block;border:1px solid var(--rule);border-radius:10px;cursor:grab;touch-action:pan-y;user-select:none;-webkit-user-select:none}
.v3-svg:active{cursor:grabbing}
.v3-svg:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.v3-bar{display:flex;flex-wrap:wrap;gap:4px;margin-top:6px}
.v3-bar button{min-width:34px;height:32px;padding:0 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink-2);font:600 .78rem var(--mono);cursor:pointer}
.v3-bar button:hover{border-color:var(--ink-3);color:var(--ink)}
.v3-bar button[aria-pressed="true"]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.v3-side{min-width:0;display:flex;flex-direction:column;gap:10px}
.v3-ctls{display:grid;gap:6px 10px;grid-template-columns:repeat(auto-fill,minmax(min(100%,200px),1fr))}
.v3-c{display:grid;grid-template-columns:1fr 78px;gap:2px 8px;align-items:center;font-size:.8rem;color:var(--ink-2);min-width:0}
.v3-c > span{grid-column:1/-1;line-height:1.35}
.v3-c i{font-style:normal;font-family:var(--mono);font-size:.72rem;color:var(--ink-3)}
.v3-c input[type=range]{width:100%;accent-color:var(--accent);min-width:0}
.v3-c input[type=number],.v3-c select{font:500 .82rem var(--mono);padding:4px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink);min-width:0;width:100%}
.v3-sel{grid-template-columns:1fr}
.v3-sel select{font-family:var(--sans)}
.v3-chk{display:flex;gap:6px;align-items:center;min-height:30px}
.v3-chk input{width:16px;height:16px;accent-color:var(--accent)}
.v3-out{display:grid;gap:4px;font-size:.82rem;min-width:0}
.v3-r{display:grid;grid-template-columns:minmax(0,1fr);gap:1px;padding:6px 10px;border-radius:7px;background:var(--paper-2);overflow-wrap:anywhere}
.v3-r > b{font:600 .74rem var(--mono);color:var(--ink-3)}
.v3-r > span{font-family:var(--mono);font-size:.82rem;line-height:1.6}
.v3-key{border-left:3px solid var(--accent);background:color-mix(in srgb,var(--accent) 8%,var(--paper))}
.v3-ok{border-left:3px solid var(--ok)}
.v3-bad{border-left:3px solid var(--c6);color:var(--c6)}
.v3-mat{display:inline-block;white-space:pre;font-family:var(--mono);line-height:1.5;padding:2px 8px;border-left:1.5px solid var(--ink);border-right:1.5px solid var(--ink)}
.v3-note{font-size:.78rem;color:var(--ink-3)}
/* svg */
.v3-svg .v3-bg{fill:var(--paper)}
.v3-svg .c1{--k:var(--c1)} .v3-svg .c2{--k:var(--c2)} .v3-svg .c3{--k:var(--c3)} .v3-svg .c4{--k:var(--c4)} .v3-svg .c5{--k:var(--c5)} .v3-svg .c6{--k:var(--c6)} .v3-svg .c7{--k:var(--c7)}
.v3-svg .ax0,.v3-svg .v3-ax0{--k:var(--axx)} .v3-svg .ax1,.v3-svg .v3-ax1{--k:var(--axy)} .v3-svg .ax2,.v3-svg .v3-ax2{--k:var(--axz)}
.v3-svg .v3-g{stroke:var(--rule);stroke-width:.7}
.v3-svg .v3-g0{stroke:var(--rule);stroke-width:1.1}
.v3-svg line.v3-ax{stroke:var(--k);stroke-width:1.3}
.v3-svg .v3-neg{stroke-dasharray:3 4;opacity:.45}
.v3-svg .v3-ax line{stroke:var(--k);stroke-width:1.4px!important;opacity:.9}
.v3-svg .v3-ax .v3-head{fill:var(--k)}
.v3-svg .v3-tk{font:500 10px var(--mono);fill:var(--ink-3)}
.v3-svg .v3-axl{font:700 15px var(--serif);font-style:italic;fill:var(--k)}
.v3-svg .v3-v line{stroke:var(--k);stroke-linecap:round}
.v3-svg .v3-v .v3-head{fill:var(--k)}
.v3-svg .v3-v .v3-end{fill:var(--paper);stroke:var(--k);stroke-width:2}
.v3-svg .v3-v .v3-x{stroke:var(--k);stroke-width:2}
.v3-svg .v3-v.v3-dash line{stroke-dasharray:6 5}
.v3-svg .v3-v.v3-thin line{stroke-width:1.6px!important}
.v3-svg .v3-fr line{opacity:.75}
.v3-svg .v3-fr .v3-head{opacity:.85}
.v3-svg .v3-l{stroke:var(--k);stroke-width:1.6;fill:none;stroke-linejoin:round}
.v3-svg .v3-l.v3-dash{stroke-dasharray:5 4}
.v3-svg .v3-l.v3-thin{stroke-width:1;opacity:.75}
.v3-svg polyline.v3-l.c4{stroke-width:2.2}
.v3-svg .v3-poly{fill:color-mix(in srgb,var(--k) 17%,transparent);stroke:var(--k);stroke-width:1;stroke-opacity:.6}
.v3-svg .v3-pt{fill:var(--k);stroke:var(--paper);stroke-width:2}
.v3-svg .v3-arc{fill:none;stroke:var(--k);stroke-width:1.8}
.v3-svg .v3-lb{font:600 14px var(--sans);fill:var(--k,var(--ink));paint-order:stroke;stroke:var(--paper);stroke-width:3.5px;stroke-linejoin:round}
.v3-svg .v3-lb.v3-sm{font-size:12.5px}
.v3-svg .v3-hint{font:500 10.5px var(--mono);fill:var(--ink-3);opacity:.85}
@media (max-width:560px){.v3d,.v3d-studio,.mech-lab,.fld-lab,.ph-lab{padding:10px}.v3-svg .v3-lb{font-size:19px}.v3-svg .v3-axl{font-size:21px}.v3-svg .v3-tk{font-size:13px}.v3-svg .v3-hint{display:none}}
/* Vector Studio */
.vs-head{display:flex;flex-wrap:wrap;gap:8px 16px;align-items:end;justify-content:space-between;margin-bottom:10px}
.lesson .vs-head h3{margin:0;font-size:1.15rem}
.vs-head .eyebrow{margin:0 0 4px}
.vs-pre{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.vs-pre label{font-size:.82rem;color:var(--ink-2);display:flex;gap:6px;align-items:center}
.vs-pre select{font:500 .84rem var(--sans);padding:6px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);max-width:260px}
.vs-dim{display:inline-flex;border:1px solid var(--rule);border-radius:8px;overflow:hidden}
.vs-dim button{padding:6px 14px;border:0;background:var(--paper);color:var(--ink-2);font:600 .82rem var(--mono);cursor:pointer}
.vs-dim button[aria-pressed="true"]{background:var(--ink);color:var(--paper)}
.vs-body{display:grid;gap:14px;grid-template-columns:minmax(0,1fr)}
@container (min-width:900px){.vs-body{grid-template-columns:minmax(0,1.3fr) minmax(330px,1fr);align-items:start}}
.vs-fig{min-width:0}
.vs-side{display:flex;flex-direction:column;gap:10px;min-width:0}
.vs-list{display:grid;gap:5px}
.vs-row{display:flex;gap:4px;align-items:center;min-width:0}
.vs-sw{display:inline-block;width:10px;height:22px;border-radius:3px;background:var(--k,var(--ink));flex:none;margin-right:2px;vertical-align:middle}
.vs-sw.c1{--k:var(--c1)} .vs-sw.c2{--k:var(--c2)} .vs-sw.c3{--k:var(--c3)} .vs-sw.c4{--k:var(--c4)} .vs-sw.c5{--k:var(--c5)} .vs-sw.c6{--k:var(--c6)} .vs-sw.c7{--k:var(--c7)}
.vs-t .vs-sw{height:12px;width:8px}
.vs-row input{font:500 .82rem var(--mono);padding:5px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink);min-width:0}
.vs-n{width:50px;flex:none;font-family:var(--sans)!important;font-weight:600!important}
.vs-x{flex:1 1 60px;width:60px}
.vs-on{display:flex;align-items:center;gap:2px;font-size:.74rem;color:var(--ink-3);flex:none}
.vs-on input{width:15px;height:15px;accent-color:var(--accent)}
.vs-star,.vs-del{flex:none;width:26px;height:28px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink-3);cursor:pointer;font-size:.85rem;padding:0}
.vs-star.on{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.vs-del:hover{border-color:var(--c6);color:var(--c6)}
.vs-add{display:flex;flex-wrap:wrap;gap:6px;align-items:center}
.vs-unit{font-size:.78rem;color:var(--ink-3);display:flex;gap:4px;align-items:center}
.vs-unit input{width:60px;font:500 .8rem var(--mono);padding:4px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink)}
.vs-abf{display:flex;flex-wrap:wrap;gap:6px;align-items:end;padding:8px;border:1px dashed var(--ink-3);border-radius:8px}
.vs-abf label{display:grid;gap:2px;font-size:.76rem;color:var(--ink-2)}
.vs-abf input{font:500 .82rem var(--mono);padding:5px 7px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink);width:120px}
.vs-opts{border:1px solid var(--rule);border-radius:10px;margin:0;padding:6px 10px 8px;display:grid;gap:2px;grid-template-columns:repeat(auto-fill,minmax(min(100%,190px),1fr))}
.vs-opts legend{font-size:.78rem;color:var(--ink-3);padding:0 4px}
.vs-opts label{display:flex;gap:6px;align-items:center;font-size:.82rem;min-height:28px}
.vs-opts input[type=checkbox]{accent-color:var(--accent);width:15px;height:15px}
.vs-eu{grid-column:1/-1;display:grid;gap:2px}
.vs-eu label{display:grid;grid-template-columns:110px 1fr 46px;gap:6px;font-size:.78rem}
.vs-eu input{accent-color:var(--accent)}
.vs-eu output{font:600 .78rem var(--mono);text-align:right}
.vs-tabs{display:flex;gap:4px;overflow-x:auto;margin:14px 0 0;border-bottom:1px solid var(--rule);scrollbar-width:thin}
.vs-tabs button{flex:none;padding:8px 12px;border:1px solid transparent;border-bottom:0;border-radius:8px 8px 0 0;background:none;color:var(--ink-2);font:600 .82rem var(--sans);cursor:pointer;white-space:nowrap}
.vs-tabs button[aria-selected="true"]{background:var(--paper);border-color:var(--rule);color:var(--ink);margin-bottom:-1px}
.vs-panel{padding:12px 0 0;min-width:0}
.vs-t{font-size:.82rem}
.vs-t td,.vs-t th{font-family:var(--mono);white-space:nowrap}
.vs-t caption{font-size:.8rem;color:var(--ink-3);text-align:left;padding:8px 0 4px}
.vs-ex{border:1px solid var(--rule);border-radius:10px;margin:8px 0;overflow:hidden}
.vs-ex-h{display:flex;flex-wrap:wrap;gap:6px;justify-content:space-between;align-items:center;padding:6px 10px;background:var(--paper-2);font-size:.84rem}
.vs-ex-h span{display:flex;gap:8px;align-items:center}
.vs-ex-h a{font-size:.8rem}
.vs-copy{font:600 .76rem var(--sans);padding:4px 10px;border:1px solid var(--rule);border-radius:6px;background:var(--card);color:var(--ink);cursor:pointer}
.vs-ex pre{margin:0;padding:10px 12px;font:500 .78rem/1.55 var(--mono);overflow-x:auto;background:var(--paper)}
.lesson .vs-exp{font-size:.84rem;color:var(--ink-2);margin:4px 0}
@media (max-width:560px){.vs-row{flex-wrap:wrap}.vs-x{flex-basis:28%}}
@media print{.v3d,.v3d-studio,.mech-lab,.fld-lab,.ph-lab{break-inside:avoid}.v3-bar,.v3-ctls,.vs-add,.vs-opts,.vs-tabs{display:none!important}}
/* mechanics lab */
.mx-fig{min-width:0}
.mx-svg{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.mx-drag .mx-svg{cursor:crosshair;touch-action:none}
.mx-svg .c1{--k:var(--c1)} .mx-svg .c2{--k:var(--c2)} .mx-svg .c3{--k:var(--c3)} .mx-svg .c4{--k:var(--c4)} .mx-svg .c5{--k:var(--c5)} .mx-svg .c6{--k:var(--c6)} .mx-svg .c7{--k:var(--c7)}
.mx-svg .ax0{--k:var(--axx)} .mx-svg .ax1{--k:var(--axy)}
.mx-a line{stroke:var(--k,var(--ink));stroke-width:2.4;stroke-linecap:round}
.mx-a polygon{fill:var(--k,var(--ink))}
.mx-a.mx-dash line{stroke-dasharray:6 5}
.mx-lb{font:600 13.5px var(--sans);fill:var(--k,var(--ink));paint-order:stroke;stroke:var(--paper);stroke-width:3.5px;stroke-linejoin:round}
.mx-cap{font:500 12.5px var(--sans);fill:var(--ink-2)}
.mx-cap.ok{fill:var(--ok);font-weight:600} .mx-cap.bad{fill:var(--c6);font-weight:600}
.mx-tk{font:500 10.5px var(--mono);fill:var(--ink-3)}
.mx-tick{stroke:var(--ink-3);stroke-width:1}
.mx-table{fill:color-mix(in srgb,var(--c5) 9%,var(--card));stroke:var(--ink-2);stroke-width:2}
.mx-pin{fill:var(--ink)}
.mx-str{stroke:var(--k);stroke-width:1.5;opacity:.8}
.mx-pulley{fill:var(--card);stroke:var(--ink-2);stroke-width:2}
.mx-ring{fill:none;stroke:var(--c6);stroke-width:3}
.mx-ring.ok{stroke:var(--ok)}
.mx-inset{fill:var(--card);stroke:var(--rule)}
.mx-tri{fill:color-mix(in srgb,var(--c5) 16%,transparent);stroke:none}
.mx-guide{stroke:var(--ink-3);stroke-width:1;stroke-dasharray:4 4;fill:none}
.mx-arc{fill:none;stroke:var(--k);stroke-width:1.8}
.mx-ceil{fill:var(--ink-3);opacity:.35}
.mx-rope{stroke:var(--ink-2);stroke-width:2}
.mx-mass{fill:color-mix(in srgb,var(--c7) 22%,var(--card));stroke:var(--ink-2);stroke-width:1.5}
.mx-ramp{fill:color-mix(in srgb,var(--c5) 14%,var(--card));stroke:var(--ink-2);stroke-width:1.5}
.mx-block{fill:color-mix(in srgb,var(--c1) 16%,var(--card));stroke:var(--ink-2);stroke-width:1.5}
.mx-beam{fill:color-mix(in srgb,var(--c7) 25%,var(--card));stroke:var(--ink-2);stroke-width:1.5}
.mx-o{fill:var(--accent);stroke:var(--paper);stroke-width:2}
.mx-sup{fill:var(--card);stroke:var(--ink-2);stroke-width:1.5}
.mx-ws{fill:color-mix(in srgb,var(--c1) 6%,transparent);stroke:var(--c1);stroke-width:1;stroke-dasharray:3 5}
.mx-ws-in{fill:var(--paper);stroke:var(--c1);stroke-width:1;stroke-dasharray:3 5}
.mx-path{fill:none;stroke:var(--c4);stroke-width:1.6;opacity:.7}
.mx-link{stroke:color-mix(in srgb,var(--c1) 30%,var(--card));stroke-width:16;stroke-linecap:round}
.mx-link.l2{stroke:color-mix(in srgb,var(--c3) 30%,var(--card));stroke-width:12}
.mx-base{fill:var(--ink-2)}
.mx-joint{fill:var(--card);stroke:var(--ink);stroke-width:2}
.mx-tip{fill:var(--c2);stroke:var(--paper);stroke-width:2}
.mx-target{stroke:var(--c6);stroke-width:2.2}
.mx-tab{font-size:.8rem}
.mx-tab td,.mx-tab th{font-family:var(--mono);white-space:nowrap;padding:4px 8px}
.mx-tab .mx-sum td{font-weight:700;border-top:2px solid var(--ink)}
@media (max-width:560px){.mx-lb{font-size:18px}.mx-cap{font-size:16px}.mx-tk{font-size:13px}}
/* field lab */
.fl-fig{min-width:0}
.fl-cv{width:100%;height:auto;aspect-ratio:640/460;display:block;border:1px solid var(--rule);border-radius:10px;touch-action:none;cursor:crosshair;background:var(--paper)}
.fld-lab[data-mode="lorentz"] .fl-cv{aspect-ratio:640/420;cursor:default;touch-action:auto}
.fl-tools{display:flex;flex-wrap:wrap;gap:5px;margin-top:6px;align-items:center}
.fl-tools button{height:32px;padding:0 10px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);font:600 .8rem var(--sans);cursor:pointer}
.fl-tools button:hover{border-color:var(--ink-3)}
.fl-tools select{height:32px;font:500 .8rem var(--sans);padding:0 6px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);max-width:100%;flex:1 1 200px}
.fl-legend{display:flex;flex-wrap:wrap;gap:4px 14px;margin-top:6px;color:var(--ink-3);font-size:.72rem}
.fl-k.a{color:var(--c2)} .fl-k.b{color:var(--c1)} .fl-k.c{color:var(--c4)} .fl-k.d{color:var(--c3)}
/* AC phasor lab */
.ph-fig{min-width:0}
.ph-circ{fill:color-mix(in srgb,var(--c5) 6%,transparent);stroke:var(--rule);stroke-width:1.2}
.ph-ax{stroke:var(--ink-3);stroke-width:1}
.ph-w{fill:none;stroke:var(--k,var(--ink));stroke-width:2.2;stroke-linejoin:round}
.ph-faint{stroke-dasharray:4 4;stroke-width:1.4;opacity:.7}
.ph-faint2{stroke-width:1.4;opacity:.55}
.ph-proj{stroke-width:4;stroke-linecap:round;opacity:.35}
.ph-proj.im{stroke:var(--c2)} .ph-proj.re{stroke:var(--c2)}
.ph-dot{fill:var(--k);stroke:var(--paper);stroke-width:2}
.ph-f0{stroke:var(--c4);stroke-width:1.4;stroke-dasharray:5 3}
.mx-svg .ph-w.c1,.mx-svg .ph-dot.c1{--k:var(--c1)}
.ph-play{margin-top:6px;height:32px;padding:0 12px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink);font:600 .8rem var(--sans);cursor:pointer}
.ph-pre{display:flex;flex-wrap:wrap;gap:5px}
.ph-pre button{font:500 .78rem var(--sans);padding:5px 10px;border:1px solid var(--rule);border-radius:999px;background:var(--paper);color:var(--ink);cursor:pointer}
.ph-pre button:hover{border-color:var(--accent)}
.ph-sw{margin-top:12px}
.ph-sweep{max-width:820px;margin:0 auto}
.ph-play{align-self:flex-start}
/* printable lab sheets */
.lab-sheet td{height:2.4em;min-width:70px}
.lab-sheet caption{font-size:.84rem;color:var(--ink-2);text-align:left;padding:6px 0;font-weight:600}
@media print{.lab-sheet td{border:1px solid #999}}
/* click-to-load external tool embeds (vector-tools page) */
.ext-embed{position:relative;border:1.5px solid var(--ink);border-radius:14px;overflow:hidden;background:#0f1a22;aspect-ratio:16/10;margin:16px 0}
.ext-embed iframe{position:absolute;inset:0;width:100%;height:100%;border:0;background:#fff}
.ext-facade{position:absolute;inset:0;display:grid;place-items:center;padding:18px;color:#e8eef3;background:radial-gradient(120% 90% at 20% 10%,color-mix(in srgb,var(--k,#2f6fd6) 45%,#0f1a22),#0f1a22 70%);text-align:center}
.ext-facade b{display:block;font:700 1.15rem/1.3 var(--serif);color:#fff;margin-bottom:6px}
.lesson .ext-facade p{margin:0 auto 12px;max-width:52ch;font-size:.88rem;color:#c7d3dc}
.ext-facade .mono{color:#9fb4c4;font-size:.72rem;display:block;margin-top:10px}
.ext-facade a{color:#9cc8ff}
.ext-facade .btn{margin:0 4px}
.ext-embed.k-phet{--k:#e86b2a} .ext-embed.k-ccak{--k:#2ba06b} .ext-embed.k-falstad{--k:#7b5cd6} .ext-embed.k-faraday{--k:#c23b6a}
@media (max-width:560px){.ext-embed{aspect-ratio:3/4}}
.tool-grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(min(100%,250px),1fr));margin:14px 0}
.tool-card{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:12px 14px;display:flex;flex-direction:column;gap:4px}
.lesson .tool-card h3{margin:0;font-size:1rem}
.lesson .tool-card p{margin:0;font-size:.86rem;color:var(--ink-2)}
.tool-card .mono{color:var(--ink-3);font-size:.72rem}
.tool-card a.go{margin-top:auto;font-weight:600;font-size:.86rem}
.v3-gal{border:1px solid var(--rule);border-radius:12px;background:var(--card);margin:8px 0;padding:0 14px}
.v3-gal > summary{cursor:pointer;padding:10px 0;font-weight:600;font-size:.94rem}
.v3-gal > summary a{font-weight:400;font-size:.84rem}
.v3-gal[open]{padding-bottom:4px}
.v3-gal .v3d{margin:6px 0 12px}
.ee-cards a.ee-card{text-decoration:none;color:inherit;transition:transform .18s,border-color .18s,box-shadow .18s}
.ee-cards a.ee-card:hover{transform:translateY(-2px);border-color:var(--accent);box-shadow:var(--shadow)}
.v3d.v3-compact{margin:0}
.v3-compact .v3-ctls{grid-template-columns:repeat(auto-fill,minmax(min(100%,150px),1fr))}
/* ==========================================================================
MATH TABS (2026-10-14): every math subject is its own top-level tab inside .
Desktop (≥1900 px): a second header row under the main menu. Hamburger: grouped under the "คณิตศาสตร์" heading.
========================================================================== */
.nav-sec{display:none}
@media (min-width:1900px){
.nav{padding-bottom:44px}
.nav-math{position:absolute;left:0;right:0;top:62px;height:44px;display:flex;align-items:center;justify-content:center;gap:26px;
border-top:1px solid var(--rule);background:color-mix(in srgb,var(--paper-2) 55%,transparent);font-size:.9rem;padding:0 20px}
.nav-math > .nav-sec{display:inline-flex;align-items:center;gap:8px;font-size:.72rem;letter-spacing:.06em;color:var(--accent);text-transform:uppercase;margin-right:2px}
.nav-math > .nav-sec::after{content:"›";font-size:1rem;color:var(--ink-3)}
.nav-math .nav-list{top:calc(100% + 11px)}
.nav-math .nav-grp::after{height:14px}
html{scroll-padding-top:120px}
.wx{scroll-margin-top:124px}
}
@media (max-width:1899px){
.nav-math{display:contents}
.nav-sec{display:block;font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);padding:18px 4px 6px;border-bottom:1px solid var(--rule)}
}
/* ==========================================================================
MATH LABS (2026-10-14): shared look for assets/lap-lab.js, calc-lab.js and la-eng.js (MathKit plots, s-plane, calculators)
========================================================================== */
.lap-lab,.cl-lab{margin:20px 0;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px 16px;display:grid;gap:10px;min-width:0;font-size:.95rem}
.lap-lab:empty,.cl-lab:empty{min-height:140px}
.lap-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px 10px}
.lap-lbl{font-family:var(--mono);font-size:.82rem;color:var(--ink-2);white-space:nowrap}
.lap-in{flex:1 1 260px;min-width:0;font:500 1rem var(--mono);padding:9px 12px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.lap-in.sm{flex:1 1 110px;max-width:170px}
.lap-in:focus{outline:2px solid var(--accent);outline-offset:1px}
.lap-chips{display:flex;flex-wrap:wrap;gap:6px}
.lap-chip{font:500 .8rem var(--sans);padding:5px 11px;border-radius:999px;border:1px solid var(--rule);background:var(--paper);color:var(--ink-2);cursor:pointer;white-space:nowrap}
.lap-chip:hover{border-color:var(--ink-3);color:var(--ink)}
.lap-chip.on{background:var(--ink);border-color:var(--ink);color:var(--paper)}
.lap-help{margin:0;font-size:.8rem;color:var(--ink-3);line-height:1.6}
.lap-help code,.lap-note code{font-size:.85em}
.lap-note{margin:4px 0;font-size:.88rem;color:var(--ink-2)}
.lap-err{margin:0;color:#c43c3c;font-weight:600}
.lap-eq{overflow-x:auto;overflow-y:hidden;max-width:100%;padding:2px 0}
.lap-eq .katex-display{margin:.35em 0!important}
.lap-ans{background:color-mix(in srgb,var(--ok) 12%,transparent);border-radius:10px;padding:6px 14px;overflow-x:auto}
.lap-steps{margin:0;padding-left:1.4em;display:grid;gap:8px}
.lap-steps > li{padding-left:2px}
.lap-steps > li > b{font-weight:600}
.lap-bh{margin:14px 0 2px;font:600 .95rem var(--sans);color:var(--accent)}
.lap-pt{border-collapse:collapse;width:100%;font-size:.86rem;margin:6px 0}
.lap-pt th,.lap-pt td{border-bottom:1px solid var(--rule);padding:5px 8px;text-align:left;vertical-align:middle}
.lap-pt th{font:500 .74rem var(--mono);color:var(--ink-3)}
.lap-pt tr.in td{background:color-mix(in srgb,var(--ok) 10%,transparent)}
.lap-plot,.lap-lab .mk-plot,.cl-lab .mk-plot{width:100%;height:auto}
.mk-plot{display:block;max-width:100%;height:auto;background:var(--paper);border-radius:10px;border:1px solid var(--rule);touch-action:none}
.mk-grid line{stroke:var(--rule);stroke-width:.8}
.mk-axis{stroke:var(--ink-3);stroke-width:1.2}
.mk-tick text,.mk-lab,.mk-ann{font:10.5px var(--mono);fill:var(--ink-3)}
.mk-lab{fill:var(--ink-2)}
.mk-ann{fill:var(--ink-2)}
.mk-drag{cursor:grab}
.mk-drag:active{cursor:grabbing}
.lap-flag{display:inline-block;font:600 .78rem var(--sans);padding:3px 10px;border-radius:999px;margin:2px 4px 2px 0}
.lap-flag.ok{background:color-mix(in srgb,var(--ok) 16%,transparent);color:var(--ok)}
.lap-flag.no{background:color-mix(in srgb,#c43c3c 13%,transparent);color:#c43c3c}
.lap-key{display:inline-block;width:18px;height:0;border-top:3px solid var(--accent);vertical-align:middle;margin:0 2px}
.lap-key.k1{border-top:2px dashed var(--ink-3)}.lap-key.k2{border-top-color:var(--accent)}.lap-key.k3{border-top:3px dotted var(--signal)}
/* s-plane */
.lap-sp{display:block;width:100%;height:auto;background:var(--paper);border:1px solid var(--rule);border-radius:12px;touch-action:none;user-select:none;-webkit-user-select:none}
.lap-g{stroke:var(--rule);stroke-width:.6}
.lap-ax{stroke:var(--ink-3);stroke-width:1.3}
.lap-jw{stroke:var(--signal);stroke-width:1.8}
.lap-tk,.lap-axl,.lap-mult,.lap-ptl{font:10.5px var(--mono);fill:var(--ink-3)}
.lap-axl{font-size:13px;fill:var(--ink-2)}
.lap-mult{font-weight:600;fill:var(--accent)}
.lap-ptl{font-size:12px;fill:var(--ink)}
.lap-roc{fill:var(--signal);opacity:.13}
.lap-rocb{stroke:var(--signal);stroke-width:1.4;stroke-dasharray:6 4}
.lap-lhp{fill:var(--ok);opacity:.06}
.lap-pole path{stroke:var(--accent);stroke-width:3;stroke-linecap:round}
.lap-pole.sel path{stroke:var(--ink)}
.lap-zero{fill:var(--paper);stroke:var(--signal);stroke-width:2.6}
.lap-zero.sel{stroke:var(--ink)}
.lap-pt.a,.lap-pt circle.a{fill:var(--accent)}
circle.lap-pt{stroke:var(--paper);stroke-width:2}
circle.lap-pt.a{fill:var(--accent)} circle.lap-pt.b{fill:var(--signal)} circle.lap-pt.c{fill:var(--ok)}
.lap-vec{stroke-width:2.4;stroke-linecap:round}
.lap-vec.a{stroke:var(--accent)} .lap-vec.b{stroke:var(--signal)} .lap-vec.c{stroke:var(--ok)}
.lap-vec.dash{stroke-dasharray:5 4;stroke-width:1.6}
.lap-rc{fill:none;stroke:var(--ok);stroke-dasharray:3 4}
.lap-poly{fill:color-mix(in srgb,var(--ok) 12%,transparent);stroke:var(--ok);stroke-width:1.2}
.lap-gx{stroke:var(--accent);stroke-width:1;fill:none;opacity:.6}
.lap-gy{stroke:var(--signal);stroke-width:1;fill:none;opacity:.6}
.lap-sq{fill:color-mix(in srgb,var(--ok) 35%,transparent);stroke:var(--ok);stroke-width:1.6}
.lap-cont{fill:color-mix(in srgb,var(--ok) 8%,transparent);stroke:var(--ok);stroke-width:2.2}
.lap-cc,.lap-cr{fill:var(--ok);stroke:var(--paper);stroke-width:2}
.lap-pz-grid,.lap-cx-grid,.lap-surf-grid{display:grid;gap:14px;align-items:start}
.lap-map-grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(min(100%,260px),1fr))}
.lap-map-grid figure{margin:0}
.lap-map-grid figcaption{color:var(--ink-3);margin-bottom:4px}
@media (min-width:860px){
.lap-pz-grid,.lap-cx-grid{grid-template-columns:minmax(0,360px) minmax(0,1fr)}
.lap-surf-grid{grid-template-columns:minmax(0,380px) minmax(0,1fr)}
}
.lap-surf-grid canvas{width:100%;max-width:380px;height:auto;border-radius:12px;border:1px solid var(--rule)}
.lap-btns{display:flex;flex-wrap:wrap;gap:6px}
.lap-roc-pick{display:flex;flex-wrap:wrap;gap:6px;align-items:center}
.lap-roc-pick .mono{width:100%;color:var(--ink-3)}
.lap-prop-cols{display:grid;gap:10px;grid-template-columns:repeat(auto-fit,minmax(min(100%,240px),1fr))}
.lap-prop-cols > div{border:1px solid var(--rule);border-radius:10px;padding:6px 12px;background:var(--paper)}
.lap-prop-cols .mono{color:var(--accent)}
.lap-fields{display:flex;flex-wrap:wrap;gap:8px}
.lap-f{display:flex;flex-direction:column;font:500 .76rem var(--mono);color:var(--ink-3);gap:2px}
.lap-f input{width:84px;font:500 .95rem var(--mono);padding:6px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink)}
.lap-lab input[type=range],.cl-lab input[type=range]{accent-color:var(--accent);flex:1 1 160px;min-width:120px}
.lap-lab output,.cl-lab output{font:600 .9rem var(--mono);min-width:3ch}
/* table of transform pairs with ROC (lesson pages) */
.lt-table td:first-child,.lt-table th:first-child{white-space:nowrap}
.lt-table td{vertical-align:middle}
.lt-fig{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(min(100%,200px),1fr));margin:14px 0}
.lt-fig figure{margin:0;border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:8px}
.lt-fig figcaption{font-size:.82rem;color:var(--ink-2);margin-top:4px;line-height:1.5}
.lt-fig svg{width:100%;height:auto;display:block}
@media print{.lap-lab,.cl-lab{display:none!important}}
/* static math figures (scripts/math_figs.py) */
svg.mf{display:block;width:100%;height:auto;max-width:100%}
.mf-bg{fill:var(--paper);stroke:var(--rule)}
.mf-g{stroke:var(--rule);stroke-width:.6}
.mf-ax{stroke:var(--ink-3);stroke-width:1.2}
.mf-jw{stroke:var(--signal);stroke-width:1.6}
.mf-t,.mf-lab{font:12px var(--sans);fill:var(--ink)}
.mf-h{font:600 12.5px var(--sans);fill:var(--ink)}
.mf-k{font:10.5px var(--mono);fill:var(--ink-3)}
.mf-l{font:12px var(--mono);fill:var(--ink-2)}
.mf-roc{fill:var(--signal);opacity:.14}
.mf-rocb{stroke:var(--signal);stroke-width:1.3;stroke-dasharray:5 4}
.mf-lhp{fill:var(--ok);opacity:.07}
.mf-pole{stroke:var(--accent);stroke-width:2.6;stroke-linecap:round;fill:none}
.mf-pole2{stroke:var(--accent);stroke-width:2;stroke-linecap:round;fill:none;opacity:.45}
.mf-zero{fill:var(--paper);stroke:var(--signal);stroke-width:2.4}
.mf-dot{fill:var(--accent)} .mf-dot2{fill:var(--accent);opacity:.35}
.mf-sig{fill:none;stroke:var(--accent);stroke-width:2;stroke-linejoin:round}
.mf-sig2{fill:none;stroke:var(--signal);stroke-width:2}
.mf-sig3{fill:none;stroke:var(--ok);stroke-width:2}
.mf-dash{fill:none;stroke:var(--ink-3);stroke-width:1.4;stroke-dasharray:5 4}
.mf-fill{fill:var(--accent);opacity:.16;stroke:none}
.mf-fill2{fill:var(--signal);opacity:.16;stroke:none}
.mf-brom{stroke:var(--ok);stroke-width:2.4}
.mf-arc{fill:none;stroke:var(--ok);stroke-width:2;stroke-dasharray:6 4}
.mf-arrow{fill:var(--ok)}
.mf-s1{fill:none;stroke:#9b59b6;stroke-width:1.8} .mf-s2{fill:none;stroke:var(--accent);stroke-width:2}
.mf-s3{fill:none;stroke:#d4a017;stroke-width:2} .mf-s4{fill:none;stroke:var(--ok);stroke-width:2.4} .mf-s5{fill:none;stroke:var(--signal);stroke-width:2}
.mf-box{fill:var(--card);stroke:var(--ink-2);stroke-width:1.4}
.mf-load{fill:var(--accent);opacity:.75}
.mf-line{stroke:var(--ink);stroke-width:2}
.mf-thin{stroke:var(--ink-3);stroke-width:1}
figure.lt-wide{margin:18px 0}
figure.lt-wide figcaption,.wx figure figcaption{font-size:.86rem;color:var(--ink-2);margin-top:6px;line-height:1.6}
.lt-practice{display:grid;gap:8px;padding-left:1.5em}
.lt-practice details{display:inline-block;margin-left:10px;vertical-align:middle}
.lt-practice summary{cursor:pointer;color:var(--signal);font-size:.86rem;font-weight:600}
.lt-practice details[open]{display:block;margin:6px 0 0;padding:8px 12px;border-radius:8px;background:color-mix(in srgb,var(--ok) 10%,transparent)}
.lt-practice .wx-btn{margin-left:8px}
.cl-sl .lap-lbl{min-width:13em;white-space:normal}
.cl-eq{overflow-x:auto}
.cl-crank-grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(min(100%,280px),1fr));align-items:start}
.cl-beam-plots{display:grid;gap:6px}
.cl-vt td{font-family:var(--mono);font-size:.82rem}
/* keep calculus labs inside the screen: the grid column must be allowed to shrink below its widest chip or slider row */
.cl-lab{grid-template-columns:minmax(0,1fr)}
@media (max-width:560px){
.cl-lab{padding:12px 10px}
.cl-lab .lap-chip{white-space:normal;text-align:left}
.cl-sl .lap-lbl{min-width:0;flex:1 1 100%}
.cl-lab input[type=range]{min-width:0}
.cl-rms .mk-tick text,.cl-rms .mk-lab,.cl-rms .mk-ann,.cl-beam .mk-tick text,.cl-beam .mk-lab,.cl-beam .mk-ann{font-size:14px}
}
/* integral engineering applications: slightly larger equations */
.int-eng .katex{font-size:1.14em}
@media (max-width:640px){
.int-eng .katex-display > .katex{font-size:1em}
.int-eng .steps .katex-display > .katex,.int-eng .tf .katex-display > .katex{font-size:.96em}
}
.la-help button{display:flex;flex-direction:column;align-items:flex-start;gap:2px;padding:12px 14px;border:1px solid var(--rule);border-radius:12px;background:var(--card);text-align:left;font:inherit;color:inherit;cursor:pointer}
.la-help button:hover{border-color:var(--accent)}
/* HOME · math subject grid (2026-10-14) */
.math-grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(min(100%,240px),1fr));margin:0 0 22px}
.math-card{position:relative;display:flex;flex-direction:column;gap:6px;padding:16px 16px 14px;border:1px solid var(--rule);border-radius:14px;background:var(--card);color:var(--ink);text-decoration:none;box-shadow:var(--shadow);transition:border-color .15s,transform .15s}
.math-card:hover,.math-card:focus-visible{border-color:var(--accent);transform:translateY(-2px)}
.math-card .mc-n{font-size:.74rem;color:var(--ink-3);letter-spacing:.06em}
.math-card .mc-sym{position:absolute;top:12px;right:14px;font:600 1.35rem/1 var(--serif);color:var(--accent);opacity:.85}
.math-card b{font:700 1.08rem/1.35 var(--serif)}
.math-card span:not(.mc-n):not(.mc-sym):not(.mc-go){font-size:.88rem;color:var(--ink-2);line-height:1.55}
.math-card em{font-style:normal;color:var(--signal);font-weight:600}
.math-card .mc-go{margin-top:auto;padding-top:4px;font:600 .84rem var(--mono);color:var(--accent)}
.math-card.hl{border-color:color-mix(in srgb,var(--accent) 55%,var(--rule));background:color-mix(in srgb,var(--accent) 6%,var(--card))}
.lap-home svg.mf text{paint-order:normal;stroke:none;font-weight:400}
.lap-home svg.mf .mf-k{font:12px var(--mono);fill:var(--ink-2)}
.lap-home svg.mf .mf-lab,.lap-home svg.mf .mf-t{font:12px var(--sans);fill:var(--ink)}
.lap-home svg.mf .mf-h{font:600 12.5px var(--sans);fill:var(--ink)}
.lap-home svg.mf .mf-l{font:12px var(--mono);fill:var(--ink-2)}
/* ===== sensors-transducers (sx) ===== */
.sx{--acc:var(--signal);--acc2:var(--accent);--mut:var(--ink-2);--line:var(--rule);--bg:var(--paper);--soft:color-mix(in srgb,var(--signal) 9%,var(--card));--warn:color-mix(in srgb,var(--accent) 12%,var(--card));--mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
.sx .sx-card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin:16px 0}
.sx .sx-grid{display:grid;gap:14px;grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}
.sx .sx-grid .sx-card{margin:0}
.sx .sx-card h3{margin-top:0}
.sx a.sx-tile{display:block;text-decoration:none;color:var(--ink);transition:.15s}
.sx a.sx-tile:hover{border-color:var(--acc);transform:translateY(-2px)}
.sx .sx-tile .sx-num{font-family:var(--mono);color:var(--acc2);font-size:13px}
.sx .sx-tag{display:inline-block;font-size:12px;border-radius:6px;padding:0 8px;background:var(--soft);color:var(--acc);margin-right:4px;font-family:var(--mono)}
.sx .sx-tag.sx-soon{background:var(--warn);color:var(--acc2)}
.sx .sx-note{border-left:4px solid var(--acc);background:var(--soft);padding:10px 16px;border-radius:0 10px 10px 0;margin:16px 0;max-width:780px}
.sx .sx-note.sx-warn{border-color:var(--acc2);background:var(--warn)}
.sx table{border-collapse:collapse;width:100%;font-size:15px;margin:12px 0;display:block;overflow-x:auto}
.sx th,.sx td{border:1px solid var(--line);padding:6px 10px;text-align:left;vertical-align:top}
.sx th{background:var(--soft);white-space:nowrap}
.sx .sx-eq{font-family:Cambria,"Times New Roman",serif;font-size:19px;text-align:center;margin:12px 0;padding:8px;background:var(--card);border:1px solid var(--line);border-radius:10px;overflow-x:auto}
.sx .sx-lab{border:2px solid var(--acc);border-radius:16px;padding:16px 18px;margin:20px 0;background:var(--card)}
.sx .sx-lab>h3{margin:0 0 6px}
.sx .sx-lab .sx-cap{font-family:var(--mono);font-size:12px;color:var(--acc);letter-spacing:.05em}
.sx .sx-row{display:flex;gap:12px;flex-wrap:wrap;align-items:end;margin:8px 0}
.sx .sx-lab label{font-size:14px;color:var(--mut);display:flex;flex-direction:column;gap:2px}
.sx .sx-lab input,.sx .sx-lab select,.sx .sx-lab button,.sx .sx-lab textarea,.sx .sx-sc input,.sx .sx-flt button{font:inherit;font-size:16px;color:var(--ink);background:var(--bg);border:1px solid var(--line);border-radius:8px;padding:6px 10px;min-width:0}
.sx .sx-lab input[type=range]{padding:0;accent-color:var(--acc)}
.sx .sx-lab button{cursor:pointer;background:var(--acc);color:#fff;border-color:var(--acc)}
.sx .sx-lab button.sx-ghost,.sx button.sx-ghost{background:transparent;color:var(--acc)}
.sx .sx-lab button:hover{opacity:.9}
.sx .sx-out{font-family:var(--mono);background:var(--bg);border:1px dashed var(--line);border-radius:10px;padding:10px 12px;margin:8px 0;overflow-x:auto;white-space:pre-wrap}
.sx .sx-big{font-size:24px;font-weight:700;color:var(--acc)}
.sx canvas,.sx svg.fig{width:100%;height:auto;display:block}
.sx svg.fig text{fill:var(--ink);font-family:inherit}
.sx .fig .l{stroke:var(--ink)}.sx .fig .a{fill:var(--acc)}.sx .fig .b{fill:var(--acc2)}
.sx figure{margin:16px 0}.sx figcaption{font-size:14px;color:var(--mut)}
.sx .sx-src{font-size:14px;color:var(--mut)}.sx .sx-src li{margin:2px 0}
.sx .sx-flt{display:flex;gap:6px;flex-wrap:wrap;margin:8px 0}
.sx .sx-flt button,.sx .sx-lab .sx-flt button{background:var(--card);color:var(--ink);border-color:var(--line);cursor:pointer;font-size:14px;padding:3px 12px;border-radius:99px;font-family:var(--mono)}
.sx .sx-lab .sx-flt button:hover{border-color:var(--acc);color:var(--acc);opacity:1}
.sx .sx-flt button[aria-pressed=true],.sx .sx-lab .sx-flt button[aria-pressed=true]{background:var(--acc);color:#fff;border-color:var(--acc)}
.sx .sx-sc{border:1px solid var(--line);border-radius:12px;padding:12px 14px;background:var(--card);margin:8px 0}
.sx .sx-sc b{color:var(--acc)}.sx .sx-sc .sx-meta{font-size:14px;color:var(--mut)}
.sx .sx-pills{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0 0}
/* ===== SENSORS SERIES: figures (scripts/sx_figs.py), widgets (sx-bus.js), plant lab (sx-plant.js) ===== */
.sx svg.xf{width:100%;height:auto;display:block;max-width:760px;margin:0 auto}
.xf .xf-bg{fill:var(--paper);stroke:var(--rule)}
.xf .xf-ln{stroke:var(--ink);stroke-width:1.6;fill:none}
.xf .xf-thin{stroke:var(--ink-3);stroke-width:1;fill:none}
.xf .xf-grid{stroke:var(--rule);stroke-width:.7}
.xf .xf-dash{stroke:var(--ink-3);stroke-width:1.2;stroke-dasharray:5 4;fill:none}
.xf .xf-a{stroke:var(--signal);stroke-width:2.2;fill:none}
.xf .xf-b{stroke:var(--accent);stroke-width:2.2;fill:none}
.xf .xf-c{stroke:var(--c3);stroke-width:2.2;fill:none}
.xf .xf-d{stroke:#9b59b6;stroke-width:2;fill:none}
.xf .xf-e{stroke:#d4a017;stroke-width:2;fill:none}
.xf .xf-box{fill:var(--card);stroke:var(--ink-2);stroke-width:1.4}
.xf .xf-boxa{fill:color-mix(in srgb,var(--signal) 12%,var(--card));stroke:var(--signal);stroke-width:1.6}
.xf .xf-boxb{fill:color-mix(in srgb,var(--accent) 12%,var(--card));stroke:var(--accent);stroke-width:1.6}
.xf .xf-boxc{fill:color-mix(in srgb,var(--c3) 12%,var(--card));stroke:var(--c3);stroke-width:1.6}
.xf .xf-fa{fill:var(--signal);opacity:.16}.xf .xf-fb{fill:var(--accent);opacity:.16}.xf .xf-fc{fill:var(--c3);opacity:.14}
.xf .xf-liq{fill:color-mix(in srgb,#2f80ed 30%,var(--card));stroke:none}
.xf .xf-metal{fill:color-mix(in srgb,var(--ink-3) 25%,var(--card));stroke:var(--ink-2);stroke-width:1.2}
.xf .xf-dot{fill:var(--accent)}.xf .xf-dota{fill:var(--signal)}.xf .xf-doto{fill:var(--paper);stroke:var(--ink);stroke-width:1.5}
.xf .xf-ah{fill:var(--ink-2)}
.xf text{font:12px var(--sans);fill:var(--ink)}
.xf .xf-h{font:600 13px var(--sans);fill:var(--ink)}
.xf .xf-k{font:10.5px var(--mono);fill:var(--ink-3)}
.xf .xf-m{font:11.5px var(--mono);fill:var(--ink-2)}
.xf .xf-ta{fill:var(--signal)}.xf .xf-tb{fill:var(--accent)}.xf .xf-tc{fill:var(--c3)}
.sx figure.xfig{margin:18px 0;padding:10px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.sx figure.xfig figcaption{margin-top:6px}
.sx .sx-seg{padding:1px 4px;border-radius:4px;margin-right:2px}
.sx .sx-seg.a{background:color-mix(in srgb,var(--c1) 22%,transparent)}.sx .sx-seg.f{background:color-mix(in srgb,var(--c2) 22%,transparent)}
.sx .sx-seg.d{background:color-mix(in srgb,var(--c3) 22%,transparent)}.sx .sx-seg.c{background:color-mix(in srgb,var(--c6) 22%,transparent)}.sx .sx-seg.m{background:color-mix(in srgb,var(--c7) 22%,transparent)}
.sx .sx-lab textarea{width:100%;font-family:var(--mono)}
.sx .sx-lab .table-wrap input{width:5.5em;font-size:15px;padding:3px 6px}
.sx .sx-tl{list-style:none;padding:0;margin:16px 0;border-left:3px solid var(--signal)}
.sx .sx-tl li{position:relative;padding:4px 0 10px 18px}
.sx .sx-tl li::before{content:"";position:absolute;left:-8px;top:10px;width:13px;height:13px;border-radius:50%;background:var(--card);border:3px solid var(--signal)}
.sx .sx-tl .yr{font-family:var(--mono);font-weight:600;color:var(--accent);margin-right:8px}
.sx .sx-tl .ct{font-size:13px;color:var(--ink-3)}
.sx-plant-wrap{border:2px solid var(--signal);border-radius:16px;background:var(--card);padding:12px;margin:18px 0}
.sx-plant-top{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:12px}
@media (max-width:860px){.sx-plant-top{grid-template-columns:1fr}}
.pl-svg{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.pl-svg text{font:11.5px var(--sans);fill:var(--ink)}
.pl-svg .pl-t{fill:var(--ink-2)}.pl-svg .pl-big{font:600 15px var(--mono);fill:var(--ink)}
.pl-svg .pl-tg{font:600 12px var(--mono)}.pl-svg .pl-ma{font:600 11.5px var(--mono);fill:var(--signal)}.pl-svg .pl-ma.bad{fill:var(--c6)}
.pl-tank{fill:none;stroke:var(--ink);stroke-width:2.4}
.pl-liq{fill:color-mix(in srgb,#2f80ed 32%,transparent)}
.pl-sp{stroke:var(--accent);stroke-width:1.6;stroke-dasharray:6 4}
.pl-pipe{fill:none;stroke:var(--ink-2);stroke-width:4;stroke-linejoin:round}.pl-pipe2{stroke:var(--ink-2);stroke-width:2}
.pl-pump{fill:var(--card);stroke:var(--ink);stroke-width:2}.pl-pump.on{fill:color-mix(in srgb,var(--c3) 30%,var(--card))}
.pl-pumpv{fill:var(--ink-2)}
.pl-valve{fill:var(--card);stroke:var(--ink);stroke-width:1.8}.pl-act{fill:var(--card);stroke:var(--ink);stroke-width:1.5}
.pl-heat{fill:none;stroke:var(--ink-3);stroke-width:3}.pl-heat.on{stroke:var(--c6)}
.pl-sig{stroke:var(--ink-3);stroke-width:1.3;stroke-dasharray:6 3 1 3}
.pl-inst circle{fill:var(--card);stroke:var(--ink);stroke-width:1.6}.pl-inst line{stroke:var(--ink);stroke-width:1.2}
.pl-plc rect{fill:color-mix(in srgb,var(--signal) 10%,var(--card));stroke:var(--signal);stroke-width:1.6}
.sx-plant-face{display:grid;gap:10px;align-content:start}
.pl-fp{border:1px solid var(--rule);border-radius:10px;padding:8px 12px;background:var(--paper);display:grid;gap:6px;font-size:14px}
.pl-fp label{display:flex;flex-wrap:wrap;align-items:center;gap:6px;color:var(--ink-2)}
.pl-fp input[type=range]{flex:1;min-width:110px;accent-color:var(--signal)}
.pl-fp input:not([type]),.pl-fp input[size]{width:4.2em;font:inherit;padding:2px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--card);color:var(--ink)}
.pl-fp select{font:inherit;padding:3px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--card);color:var(--ink);max-width:100%}
.pl-pv{font:600 22px var(--mono);color:var(--signal)}
.pl-btns{display:flex;gap:6px;flex-wrap:wrap}
.pl-btns button{font:600 13px var(--mono);padding:4px 12px;border-radius:8px;border:1px solid var(--signal);background:var(--card);color:var(--signal);cursor:pointer}
.pl-btns button[aria-pressed=true]{background:var(--signal);color:#fff}
.pl-tune{display:flex;flex-wrap:wrap;gap:8px}
.sx-plant-trend{margin-top:10px}
.sx-plant-alarm{font:13px var(--mono);margin:8px 0;padding:8px 10px;border-radius:8px;background:var(--paper);border:1px dashed var(--rule);line-height:1.6}
.sx-plant-mb summary{cursor:pointer;font-weight:600;margin:6px 0}
.sx-plant-mb table{font-size:13px}
/* tag-decoder chips: explicit black text (light) / light text (dark) so they never inherit the white lab-button colour */
.sx .sx-lab .sx-flt button.sx-chip{background:#fff;color:#111;border:1px solid #9aa3ad;font-weight:600}
.sx .sx-lab .sx-flt button.sx-chip:hover,.sx .sx-lab .sx-flt button.sx-chip[aria-pressed=true]{background:var(--signal);color:#fff;border-color:var(--signal)}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .sx .sx-lab .sx-flt button.sx-chip{background:#1d2630;color:#f2f4f6;border-color:#566270}}
:root[data-theme="dark"] .sx .sx-lab .sx-flt button.sx-chip{background:#1d2630;color:#f2f4f6;border-color:#566270}
/* ===== MOTOR CONTROL & PLC SERIES (topics 21–22 + English editions): figures (scripts/mc_figs.py), mc-calc.js, mc-lab.js, plc-sim.js ===== */
.mc{--acc:var(--signal);--acc2:var(--accent);--soft:color-mix(in srgb,var(--signal) 9%,var(--card));--warn:color-mix(in srgb,var(--accent) 12%,var(--card))}
.mc svg.xf{width:100%;height:auto;display:block;max-width:780px;margin:0 auto}
.mc figure.xfig{margin:18px 0;padding:10px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.mc figure.xfig figcaption{margin-top:6px;font-size:14px;color:var(--ink-2)}
.xf .xf-rail{stroke:var(--ink);stroke-width:2.2;fill:none}
.xf .xf-pe{stroke:#2e9b4f;stroke-width:2.2;fill:none;stroke-dasharray:10 3 2 3}
.xf .xf-shield{stroke:var(--ink);stroke-width:2;fill:none;stroke-dasharray:2 3}
.xf .xf-shaft{stroke:var(--ink-2);stroke-width:7;fill:none;stroke-linecap:round}
.xf .xf-mech{stroke:var(--ink-2);stroke-width:1.4;stroke-dasharray:3 3;fill:none}
.xf .xf-coil{fill:var(--card);stroke:var(--ink);stroke-width:1.6}
.xf .xf-fill{fill:var(--ink-2);stroke:none}
.xf .xf-estop{fill:#d63b2f;stroke:#8f1d14;stroke-width:1}
.xf .xf-estopc{fill:#d63b2f;stroke:#f2c94c;stroke-width:8}
.xf .xf-motor{fill:color-mix(in srgb,var(--signal) 10%,var(--card));stroke:var(--ink);stroke-width:1.8}
.xf .xf-term{fill:var(--card);stroke:var(--ink);stroke-width:1.4}
.xf .xf-link{fill:#c98b2b;stroke:#8a5a12;stroke-width:1}
.xf .xf-plate{fill:color-mix(in srgb,var(--ink-3) 14%,var(--card));stroke:var(--ink-2);stroke-width:1.6}
.xf .xf-plt{font:600 14px var(--mono);fill:var(--ink)}
.xf .xf-paper{fill:var(--paper);stroke:var(--rule)}
.xf .xf-duct{fill:color-mix(in srgb,var(--ink-3) 30%,var(--card));stroke:var(--ink-3);stroke-width:1}
.xf .xf-bara{fill:var(--signal);opacity:.75}.xf .xf-barb{fill:var(--accent);opacity:.75}
.xf .xf-dotk{fill:var(--ink)}
.xf .xf-tag{font:600 12px var(--mono);fill:var(--signal)}
.xf .xf-tagk{font:11px var(--mono);fill:var(--signal)}
.xf .xf-bus{stroke:var(--ink);stroke-width:6;stroke-linecap:round;fill:none}
.xf .xf-wn{font:10px var(--mono);fill:var(--ink-2)}
.xf .xf-rn{font:600 12px var(--mono);fill:var(--ink-2)}
.xf .xf-xref{fill:var(--card);stroke:var(--ink-3);stroke-width:1}
.xf .xf-colno{font:600 11px var(--mono);fill:var(--ink-2)}
.lang-sw{display:inline-flex;gap:0;border:1px solid var(--rule);border-radius:999px;overflow:hidden;margin:4px 0 10px;font:600 13px var(--mono);background:var(--card)}
.lang-sw a,.lang-sw span{display:inline-flex;align-items:baseline;gap:6px;padding:5px 14px;text-decoration:none;color:var(--ink-2)}
.lang-sw small{font:400 12px var(--sans);color:inherit;opacity:.85}
.lang-sw span[aria-current]{background:var(--signal);color:#fff}
.lang-sw a:hover{background:var(--soft,color-mix(in srgb,var(--signal) 9%,var(--card)));color:var(--signal)}
.mc .mc-note{border-left:4px solid var(--signal);background:color-mix(in srgb,var(--signal) 8%,var(--card));padding:10px 16px;border-radius:0 10px 10px 0;margin:16px 0}
.mc .mc-warn{border-left:4px solid #d63b2f;background:color-mix(in srgb,#d63b2f 9%,var(--card));padding:10px 16px;border-radius:0 10px 10px 0;margin:16px 0}
.mc .mc-ok{border-left:4px solid var(--ok);background:color-mix(in srgb,var(--ok) 9%,var(--card));padding:10px 16px;border-radius:0 10px 10px 0;margin:16px 0}
.mc .mc-grid{display:grid;gap:14px;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));margin:14px 0}
.mc .mc-card{background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:14px 16px}
.mc .mc-card h3{margin:0 0 6px;font-size:1.02rem}
.mc .mc-card p{margin:4px 0;font-size:.95rem}
.mc pre.code{background:#0f1620;color:#e6edf3;border-radius:10px;padding:12px 14px;overflow-x:auto;font:13.5px/1.5 var(--mono);margin:12px 0}
.mc pre.code .k{color:#ff9e64}.mc pre.code .c{color:#7f8c98}.mc pre.code .s{color:#9ece6a}
.mc .chk{list-style:none;padding-left:0}.mc .chk li{padding-left:26px;position:relative;margin:4px 0}
.mc .chk li::before{content:"☐";position:absolute;left:0;color:var(--signal)}
/* motor starter simulator (assets/mc-lab.js) */
.mc-lab{border:2px solid var(--signal);border-radius:16px;background:var(--card);padding:12px;margin:18px 0}
.mcl-tabs{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:10px}
.mcl-tabs button{font:600 13px var(--sans);padding:5px 12px;border-radius:999px;border:1px solid var(--signal);background:var(--card);color:var(--signal);cursor:pointer}
.mcl-tabs button[aria-pressed=true]{background:var(--signal);color:#fff}
.mcl-body{display:grid;grid-template-columns:minmax(0,0.9fr) minmax(0,1.1fr);gap:12px}
@media (max-width:860px){.mcl-body{grid-template-columns:1fr}}
.mcl-sv{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.mcl-sv text{font:11px var(--mono);fill:var(--ink-2)}
.mcl-sv .mcl-t{fill:var(--ink-3)}
.mcl-sv .mcl-bt{font:600 12px var(--mono);fill:var(--ink);text-anchor:middle}
.mcl-sv .mcl-bs{font:10.5px var(--mono);fill:var(--ink-3);text-anchor:middle}
.mcl-sv .mcl-rail{stroke:var(--ink);stroke-width:2.4}
.mcl-sv .mcl-hot{stroke:#e0452b;stroke-width:3}
.mcl-sv .mcl-cold{stroke:var(--ink-3);stroke-width:1.6}
.mcl-sv .mcl-box{fill:var(--card);stroke:var(--ink-3);stroke-width:1.4}
.mcl-sv .mcl-box.on{fill:color-mix(in srgb,#2e9b4f 26%,var(--card));stroke:#2e9b4f;stroke-width:2.2}
.mcl-sv .mcl-motor{fill:color-mix(in srgb,var(--signal) 12%,var(--card));stroke:var(--ink);stroke-width:2}
.mcl-sv .mcl-motor.spin{stroke:#2e9b4f;stroke-width:3;stroke-dasharray:8 4}
.mcl-btns{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0}
.mcl-pb{font:700 14px var(--sans);padding:10px 16px;border-radius:12px;border:2px solid;cursor:pointer;touch-action:none;user-select:none}
.mcl-pb.g{background:#1f8a45;border-color:#14612f;color:#fff}.mcl-pb.r{background:#c73228;border-color:#8f1d14;color:#fff}.mcl-pb.y{background:#f2c94c;border-color:#b18a12;color:#1b1b1b}
.mcl-pb.on{transform:translateY(2px);filter:brightness(.85)}
.mcl-logic{font:13px var(--mono);margin:6px 0;padding-left:20px;color:var(--ink-3)}
.mcl-logic li.on{color:#1f8a45;font-weight:600}
.mcl-meters{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:6px}
.mcl-m{border:1px solid var(--rule);border-radius:10px;padding:6px 8px;background:var(--paper)}
.mcl-m span{display:block;font-size:12px;color:var(--ink-3)}.mcl-m b{font:600 20px var(--mono);color:var(--ink)}.mcl-m i{display:block;font:11px var(--mono);color:var(--ink-3);font-style:normal}
.mcl-m.a b{color:var(--signal)}.mcl-m.b b{color:var(--ok)}.mcl-m.c b{color:var(--accent)}
.mcl-chart{width:100%;height:auto;display:block;margin-top:8px;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.mcl-leg{display:flex;gap:14px;flex-wrap:wrap;font:12px var(--mono);margin:4px 0}
.mcl-leg span::before{content:"";display:inline-block;width:14px;height:3px;margin-right:6px;vertical-align:middle}
.mcl-leg .a::before{background:var(--signal)}.mcl-leg .b::before{background:var(--ok)}.mcl-leg .c::before{background:var(--accent)}
.mcl-set{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:6px 12px;margin-top:8px}
.mcl-r{display:flex;flex-wrap:wrap;align-items:center;gap:6px;font-size:13px;color:var(--ink-2)}
.mcl-r span{flex:1 1 100%}.mcl-r input[type=range]{flex:1;accent-color:var(--signal)}.mcl-r output{font:12px var(--mono);min-width:5em}
.mcl-r select{font:inherit;padding:3px 6px;border:1px solid var(--rule);border-radius:6px;background:var(--paper);color:var(--ink);max-width:100%}
.mcl-c{display:flex;gap:6px;align-items:flex-start;font-size:13px;color:var(--ink-2)}
.mcl-msg{min-height:1.4em;font:600 14px var(--sans);color:#c73228;margin:6px 0 0}
/* PLC ladder simulator (assets/plc-sim.js) */
.plc-sim{border:2px solid var(--signal);border-radius:16px;background:var(--card);padding:12px;margin:18px 0}
.ps-bar{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin-bottom:10px}
.ps-bar select{font:inherit;font-size:15px;padding:5px 8px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);max-width:100%}
.ps-run{font:700 13px var(--mono);padding:6px 14px;border-radius:8px;border:none;background:#1f8a45;color:#fff;cursor:pointer}.ps-run.off{background:#c73228}
.ps-scan{display:flex;align-items:center;gap:6px;font-size:13px;color:var(--ink-2)}.ps-scan input{accent-color:var(--signal);width:120px}.ps-scan output{font:12px var(--mono)}
.ps-cnt{font-size:12px;color:var(--ink-3)}
.ps-grid{display:grid;grid-template-columns:minmax(220px,0.38fr) minmax(0,1fr);gap:12px}
@media (max-width:860px){.ps-grid{grid-template-columns:1fr}}
.ps-h{font:600 13px var(--sans);color:var(--ink-2);margin:4px 0}
.ps-in,.ps-out{display:grid;gap:6px}
.ps-ib{display:grid;grid-template-columns:auto 1fr auto;gap:8px;align-items:center;text-align:left;font:13px var(--sans);padding:7px 10px;border-radius:10px;border:1px solid var(--rule);background:var(--paper);color:var(--ink);cursor:pointer;touch-action:none;user-select:none}
.ps-ib b{font:600 12px var(--mono);color:var(--signal)}.ps-ib i{width:12px;height:12px;border-radius:50%;background:var(--rule)}
.ps-ib.on i{background:#2e9b4f;box-shadow:0 0 8px #2e9b4f}.ps-ib.act{border-color:var(--signal);background:color-mix(in srgb,var(--signal) 12%,var(--paper))}
.ps-ib.ncpush,.ps-ib.nctoggle{border-style:dashed}.ps-ib:disabled{cursor:default;opacity:.85}
.ps-ob{display:grid;grid-template-columns:auto auto 1fr;gap:4px 8px;align-items:center;font:13px var(--sans);padding:6px 10px;border-radius:10px;border:1px solid var(--rule);background:var(--paper)}
.ps-ob i{width:14px;height:14px;border-radius:50%;background:var(--rule);grid-row:span 2}
.ps-ob b{font:600 12px var(--mono);color:var(--ink-2)}.ps-ob em{grid-column:2/4;font:11px var(--mono);font-style:normal;color:var(--ink-3);position:relative}
.ps-ob em span{display:block;height:4px;background:var(--signal);border-radius:2px;margin-top:3px}
.ps-ob.on.green i,.ps-ob.on.motor i{background:#2e9b4f;box-shadow:0 0 8px #2e9b4f}.ps-ob.on.amber i{background:#f2a51a;box-shadow:0 0 8px #f2a51a}.ps-ob.on.red i{background:#e0452b;box-shadow:0 0 8px #e0452b}
.ps-ob.on.mem i,.ps-ob.on.tmr i,.ps-ob.on.ctr i{background:var(--signal)}
.ps-ob.motor i{border-radius:3px}
.ps-lad{overflow-x:auto;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.ps-svg{width:100%;height:auto;display:block}
.ps-svg .rail{stroke:var(--ink);stroke-width:3}
.ps-svg .lc{stroke:var(--ink-3);stroke-width:1.6}.ps-svg .lh{stroke:#1f9a4a;stroke-width:3.4}
.ps-svg .ct line{stroke:var(--ink);stroke-width:2}.ps-svg .ct.cl line{stroke:#1f9a4a;stroke-width:2.6}
.ps-svg text{font:11px var(--mono);fill:var(--ink-2);text-anchor:middle}
.ps-svg .vn{font:600 11.5px var(--mono);fill:var(--signal)}.ps-svg .vl{font:10px var(--sans);fill:var(--ink-3)}.ps-svg .ek{font:700 11px var(--mono);fill:var(--ink)}
.ps-svg .rn{fill:var(--ink-3);text-anchor:start}.ps-svg .cm{fill:var(--ink-3);text-anchor:start;font-size:10.5px}
.ps-svg .coil{fill:none;stroke:var(--ink);stroke-width:2}.ps-svg .coil.on{stroke:#1f9a4a;stroke-width:3}
.ps-svg .fb{fill:var(--card);stroke:var(--ink);stroke-width:1.6}.ps-svg .fb.on{stroke:#1f9a4a;stroke-width:2.6}
.ps-svg .fbt{font:700 12px var(--mono);fill:var(--ink)}.ps-svg .fbs{font:10.5px var(--mono)}.ps-svg .pin{text-anchor:start;font-size:10px;fill:var(--ink-3)}
.ps-ed{margin-top:10px}.ps-ed summary{cursor:pointer;font-weight:600}
.ps-ed textarea{width:100%;font:13.5px/1.5 var(--mono);background:#0f1620;color:#e6edf3;border-radius:10px;padding:10px;border:1px solid var(--rule);margin-top:6px}
.ps-edb{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin-top:6px}
.ps-edb button{font:600 13px var(--sans);padding:6px 14px;border-radius:8px;border:none;background:var(--signal);color:#fff;cursor:pointer}
.ps-help{font:12px var(--mono);color:var(--ink-3)}
.ps-err{color:#c73228;font:12.5px var(--mono);white-space:pre-wrap;margin:6px 0}
.ps-plant{margin-top:8px}
.ps-sv{width:100%;max-width:300px;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px}
.ps-sv text{font:11px var(--mono);fill:var(--ink-2)}.ps-sv .big{font:700 16px var(--mono);fill:var(--ink)}.ps-sv .bad{fill:#e0452b}
.ps-sv .tk{fill:none;stroke:var(--ink);stroke-width:2.4}.ps-sv .liq{fill:color-mix(in srgb,#2f80ed 35%,transparent)}
.ps-sv .lsw{stroke:var(--ink-3);stroke-width:3}.ps-sv .lsw.on{stroke:#1f9a4a}
.ps-sv .pm{fill:var(--card);stroke:var(--ink);stroke-width:2}.ps-sv .pm.on{fill:color-mix(in srgb,#2e9b4f 40%,var(--card))}
.ps-sv .pp{fill:none;stroke:var(--ink-2);stroke-width:3}.ps-sv .vv{fill:var(--card);stroke:var(--ink)}.ps-sv .vv.on{fill:#2e9b4f}
.ps-sv .belt{fill:var(--ink-3)}.ps-sv .belt.on{fill:#2e9b4f}.ps-sv .box{fill:#c98b2b;stroke:#8a5a12}
.ps-sv .eye{stroke:var(--ink-3);stroke-width:2;stroke-dasharray:4 3}.ps-sv .eye.on{stroke:#e0452b;stroke-width:3}
.ps-sv .hs{fill:#222b33}.ps-sv .tl{fill:#3a434b}.ps-sv .tl.r.on{fill:#ff4d3d}.ps-sv .tl.y.on{fill:#ffc43d}.ps-sv .tl.g.on{fill:#33d17a}
.ps-sv .w{stroke:var(--ink-3);stroke-width:3}.ps-sv .w.on{stroke:#e0452b}
/* ==========================================================================
BUCK CONVERTER DEEP-DIVE LABS (/learn/power-electronics/buck-*) — assets/buck-core.js, buck-ui.js, buck-lab.js, buck-design.js
========================================================================== */
.bk-lab{--bk5:#8a5fc4;margin:22px 0;border:1.5px solid var(--ink);border-radius:14px;background:var(--card);padding:14px;display:grid;gap:12px;min-width:0}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .bk-lab{--bk5:#b394e6}}
:root[data-theme="dark"] .bk-lab{--bk5:#b394e6}
.bk-lab:not(.bk-ready){min-height:260px}
.bk-lab > *{min-width:0}
.bk-lab noscript{display:block;padding:12px;color:var(--ink-3)}
.bk-top{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center}
.bk-presets{display:flex;flex-wrap:wrap;gap:6px}
.bk-presets .btn.on,.bk-lab .btn.on{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.bk-grid{display:grid;grid-template-columns:minmax(230px,290px) minmax(0,1fr);gap:14px;align-items:start}
.bk-grid.wide{grid-template-columns:minmax(0,1fr)}
@media (max-width:900px){.bk-grid{grid-template-columns:minmax(0,1fr)}}
.bk-ctl{display:grid;gap:8px;border:1px solid var(--rule);border-radius:10px;padding:10px 12px;background:var(--paper);min-width:0;align-content:start}
.bk-ctl h4,.bk-lab h4{margin:0 0 2px;font:700 .9rem var(--sans)}
.bk-f{display:grid;grid-template-columns:minmax(0,1fr) 92px;gap:2px 8px;align-items:center;font-size:.84rem;min-width:0}
.bk-f > label{grid-column:1/-1;display:flex;justify-content:space-between;gap:6px;color:var(--ink-2)}
.bk-f > label em{font-style:normal;font:.72rem var(--mono);color:var(--ink-3)}
.bk-f input[type=range]{width:100%;min-width:0;accent-color:var(--accent);margin:0}
.bk-f input[type=number],.bk-lab select,.bk-lab input[type=text]{font:500 .84rem var(--sans);padding:4px 7px;border-radius:7px;border:1px solid var(--rule);background:var(--paper);color:var(--ink);min-width:0;max-width:100%}
.bk-f input[type=number]{width:100%}
.bk-lab select{width:100%}
.bk-sw{display:grid;gap:4px;font-size:.84rem}
.bk-sw > span{font:.72rem var(--mono);color:var(--ink-3)}
.bk-sw label,.bk-chk{display:flex;gap:6px;align-items:center;font-size:.84rem;color:var(--ink-2);cursor:pointer}
.bk-more{border-top:1px dashed var(--rule);padding-top:6px}
.bk-more summary{cursor:pointer;font-size:.86rem;font-weight:600}
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.bk-out{display:grid;gap:10px;min-width:0}
.bk-status{font-size:.9rem;line-height:1.7;padding:8px 12px;border-radius:10px;background:var(--paper-2);border-left:4px solid var(--accent);overflow-wrap:anywhere}
.bk-badge{display:inline-block;font:700 .72rem var(--mono);padding:1px 8px;border-radius:999px;color:var(--accent-ink);vertical-align:1px}
.bk-badge.ccm{background:var(--signal)} .bk-badge.dcm{background:var(--accent)}
.bk-figs{display:grid;gap:10px}
.bk-fig{min-width:0}
.bk-fig:empty{display:none}
.bk-svg{width:100%;height:auto;display:block;background:var(--paper);border:1px solid var(--rule);border-radius:10px;touch-action:pan-y}
.bk-gr{stroke:var(--rule);stroke-width:1}
.bk-frame{fill:none;stroke:var(--ink-3);stroke-width:1}
.bk-tk{font:11px var(--mono);fill:var(--ink-3)}
.bk-al{font:12px var(--sans);fill:var(--ink-2)}
.bk-title{font:600 13px var(--sans);fill:var(--ink)}
.bk-line{fill:none;stroke-width:2;stroke-linejoin:round;stroke-linecap:round}
.bk-line.dash{stroke-dasharray:6 4}
.bk-line.fill{fill:color-mix(in srgb,currentColor 0%,transparent)}
.bk-line.s1,.bk-pt.s1{stroke:var(--signal)} .bk-line.s2,.bk-pt.s2{stroke:var(--accent)} .bk-line.s3,.bk-pt.s3{stroke:var(--ok)} .bk-line.s4,.bk-pt.s4{stroke:var(--ink-3)} .bk-line.s5,.bk-pt.s5{stroke:var(--bk5)}
.bk-pt{stroke-width:2}
.bk-pt.s1{fill:var(--signal)} .bk-pt.s2{fill:var(--accent)} .bk-pt.s3{fill:var(--ok)} .bk-pt.s4{fill:var(--ink-3)} .bk-pt.s5{fill:var(--bk5)}
.bk-pt{stroke:var(--card)}
.bk-pl{font:600 11px var(--sans);fill:var(--ink)}
.bk-band.on{fill:color-mix(in srgb,var(--signal) 9%,transparent)}
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.bk-band.idle{fill:color-mix(in srgb,var(--ink-3) 14%,transparent)}
.bk-band.bad{fill:color-mix(in srgb,#c0392b 14%,transparent)}
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.bk-bl{font:600 10.5px var(--mono);fill:var(--ink-3)}
.bk-ref{stroke:var(--ink-3);stroke-dasharray:3 4;stroke-width:1}
.bk-ref.s2{stroke:var(--accent)} .bk-ref.s1{stroke:var(--signal)}
.bk-rl{font:10.5px var(--mono);fill:var(--ink-3)} .bk-rl.s2{fill:var(--accent)} .bk-rl.s1{fill:var(--signal)}
.bk-lg text{font:11px var(--sans);fill:var(--ink-2)}
.bk-cross{stroke:var(--ink);stroke-width:1;stroke-dasharray:2 3}
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.bk-ro{font:.76rem var(--mono);color:var(--ink-2);min-height:1.5em;padding:3px 4px;overflow-wrap:anywhere}
.bk-tbl{overflow-x:auto}
.bk-t{width:100%;border-collapse:collapse;font-size:.84rem}
.bk-t th,.bk-t td{border-bottom:1px solid var(--rule);padding:5px 8px;text-align:left;vertical-align:top}
.bk-t th{font:600 .74rem var(--mono);color:var(--ink-3);background:var(--paper-2)}
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.bk-t tr.bad td{color:#c0392b} .bk-t tr.warn td{color:#a8650a}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .bk-t tr.bad td{color:#ff8a7a}:root:not([data-theme="light"]) .bk-t tr.warn td{color:#f0b35a}}
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.bk-note{font-size:.8rem;line-height:1.6;color:var(--ink-3);margin:2px 0}
.bk-mat{border-collapse:separate;border-spacing:0;margin:2px 6px;display:inline-table;vertical-align:middle;border-left:2px solid var(--ink-2);border-right:2px solid var(--ink-2);border-radius:5px}
.bk-mat td{padding:2px 9px;text-align:right;font:.8rem var(--mono);white-space:nowrap}
.bk-eqs{display:grid;gap:8px;font-size:.88rem}
.bk-eq{border:1px solid var(--rule);border-radius:10px;padding:8px 12px;background:var(--paper);overflow-x:auto}
.bk-eq h5{margin:0 0 4px;font:700 .8rem var(--mono);color:var(--accent)}
.bk-eq .row{display:flex;flex-wrap:wrap;gap:4px 10px;align-items:center;line-height:2}
.bk-eq .ex{color:var(--ink-3);font-size:.78rem;display:block}
.bk-pass{color:var(--ok);font-weight:700} .bk-fail{color:#c0392b;font-weight:700} .bk-warnc{color:#a8650a;font-weight:700}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .bk-fail{color:#ff8a7a}:root:not([data-theme="light"]) .bk-warnc{color:#f0b35a}}
:root[data-theme="dark"] .bk-fail{color:#ff8a7a} :root[data-theme="dark"] .bk-warnc{color:#f0b35a}
.bk-prog{width:100%;border-collapse:collapse;font-size:.84rem}
.bk-prog th{font:600 .72rem var(--mono);color:var(--ink-3);text-align:left;padding:4px}
.bk-prog td{padding:3px 4px}
.bk-prog input,.bk-prog select{width:100%;min-width:60px}
.bk-run{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.bk-busy{font:.76rem var(--mono);color:var(--ink-3)}
.bk-lab .btn-sm{min-height:34px}
.bk-two{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
@media (max-width:760px){.bk-two{grid-template-columns:minmax(0,1fr)}}
.bk-callout{border:1.5px solid var(--accent);border-radius:12px;padding:12px 16px;background:color-mix(in srgb,var(--accent) 6%,var(--card));margin:16px 0}
.bk-callout h3,.bk-callout h4{margin:0 0 6px}
.bk-path{display:grid;gap:8px;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));margin:12px 0;padding:0;list-style:none}
.bk-path li{border:1px solid var(--rule);border-radius:10px;padding:10px 12px;background:var(--card)}
.bk-path li b{display:block;font-size:.92rem}
.bk-path li span{font-size:.8rem;color:var(--ink-3)}
.bk-path a{text-decoration:none;color:inherit;display:block}
.bk-path li:hover{border-color:var(--accent)}
.bk-fig-static{margin:14px 0;text-align:center}
.bk-fig-static svg{max-width:100%;height:auto;background:var(--paper);border:1px solid var(--rule);border-radius:10px;color:var(--ink)}
.bk-fig-static figcaption{font-size:.82rem;color:var(--ink-3);margin-top:4px}
.bk-sch{fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
.bk-sch text{fill:currentColor;stroke:none;font:13px var(--mono)}
.bk-sch .hot{stroke:var(--accent);stroke-width:3.2}
.bk-sch .hot2{stroke:var(--signal);stroke-width:3.2}
.bk-sch .dim{opacity:.35}
.bk-sch .lbl{fill:var(--accent);stroke:none;font:600 12px var(--sans)}
.bk-sch .lbl2{fill:var(--signal);stroke:none;font:600 12px var(--sans)}
@media print{.bk-lab{display:none!important}}
.bk-sel{display:grid;gap:3px;font-size:.84rem}
.bk-sel label{color:var(--ink-2)}
.bk-run label{display:flex;gap:6px;align-items:center;font-size:.84rem;color:var(--ink-2)}
.bk-run select{width:auto}
.bk-n{display:grid;grid-template-columns:minmax(0,1fr) 96px 44px;gap:6px;align-items:center;font-size:.84rem;color:var(--ink-2)}
.bk-n input{width:100%;font:500 .84rem var(--sans);padding:4px 7px;border-radius:7px;border:1px solid var(--rule);background:var(--paper);color:var(--ink);min-width:0}
.bk-n em{font-style:normal;font:.72rem var(--mono);color:var(--ink-3)}
.pinfo{margin:-2px 0 4px;min-height:1.2em}
.bk-prog select{min-width:150px}
.bk-prog input[type=number]{min-width:70px}
.bk-ws{border:1px solid var(--rule);border-left:4px solid var(--accent);border-radius:10px;background:var(--card);padding:10px 14px;margin:10px 0}
.bk-ws p{margin:0 0 8px}
.bk-ws .bk-q{color:var(--ink-3);font-size:.86rem}
.bk-chk-list{margin:6px 0 0;padding-left:1.2em}
.bk-staticsvg{max-width:100%;height:auto}
.bk-fig-static .bk-staticsvg .bk-ref{stroke-dasharray:3 4}
.tbl-sm{font-size:.88rem}
.lesson .bk-path{max-width:none;margin:12px 0;padding:0;list-style:none}
.lesson .bk-path li{margin:0}
/* ---- Blog (/blog/) ---- */
.blog-grid{display:grid;gap:14px}
@media (min-width:700px){.blog-grid{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1050px){.blog-grid{grid-template-columns:repeat(3,1fr)}}
.blog-card{display:flex;flex-direction:column;gap:8px;text-decoration:none;background:var(--card);border:1px solid var(--rule);border-radius:12px;padding:20px;
transition:transform .18s,border-color .18s,box-shadow .18s}
.blog-card:hover{transform:translateY(-3px);border-color:var(--accent);box-shadow:var(--shadow)}
.blog-card b{font-size:1.06rem;line-height:1.4;color:var(--ink)}
.bc-tag{align-self:flex-start;font-size:.72rem;color:var(--accent);border:1px solid var(--rule);border-radius:999px;padding:2px 10px}
.bc-sum{color:var(--ink-2);font-size:.92rem;line-height:1.55}
.bc-foot{display:flex;justify-content:space-between;gap:10px;margin-top:auto;padding-top:6px;font-family:var(--mono);font-size:.76rem;color:var(--ink-3)}
.bc-go{color:var(--accent)}
.post-more{margin-top:56px}
.post-box{margin:40px 0 0;padding:18px 22px;border:1px solid var(--rule);border-left:4px solid var(--signal);border-radius:12px;background:var(--card)}
.post-box-h{font-family:var(--serif);font-weight:700;font-size:1.1rem;margin:0 0 8px}
.post-box ul{margin:0 0 8px}
.post-next{margin:36px 0 0;padding:18px 22px;border:1px solid var(--rule);border-left:4px solid var(--accent);border-radius:12px;background:var(--card)}
.post-next h2{font-size:1.15rem;margin:0 0 8px;padding:0}
.post-next ul{margin:0}
/* BLOG CATEGORIES (added 2026-10-25): chips on /blog/ and the category pages, one section per category on the hub,
the category link under "more articles" in a post. The markup comes from build.mjs (BLOG_CATS). */
.blog-chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:22px}
.blog-chips a{display:inline-flex;align-items:center;gap:8px;padding:7px 14px;border:1px solid var(--rule);border-radius:999px;background:var(--card);color:var(--ink);text-decoration:none;font-weight:600;font-size:.9rem}
.blog-chips a span{font-family:var(--serif);color:var(--accent)}
.blog-chips a small{font:500 .74rem var(--mono);color:var(--ink-3)}
.blog-chips a:hover{border-color:var(--accent)}
.blog-chips a[aria-current]{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 12%,var(--card))}
.blog-sub{font-size:1.25rem;margin:8px 0 14px}
.blog-cat{margin-top:44px;scroll-margin-top:90px}
.blog-cat-head{display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:6px 16px;margin-bottom:6px}
.blog-cat-head h2{margin:0;scroll-margin-top:90px;font-size:clamp(1.35rem,2.6vw,1.7rem)}
.blog-cat-head h2 a{color:inherit;text-decoration:none}
.blog-cat-head h2 a:hover{color:var(--accent)}
.blog-cat-head h2 small{font:500 .8rem var(--mono);color:var(--ink-3);margin-left:6px}
.blog-cat-head .mono{font-size:.8rem;color:var(--ink-3)}
.blog-cat-sym{font-family:var(--serif);color:var(--accent);margin-right:10px}
.blog-cat-desc{margin:0 0 14px;color:var(--ink-2);max-width:72ch}
.post-cat-link{margin:16px 0 0;font-size:.95rem}
.post-table{width:100%;border-collapse:collapse;margin:0 0 18px;font-size:.95rem}
.post-table th,.post-table td{border:1px solid var(--rule);padding:8px 12px;text-align:left;vertical-align:top}
.post-table th{background:var(--paper-2);font-weight:600}
.post-table-wrap{overflow-x:auto;margin:0 0 18px}
.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
/* ==========================================================================
SEQUENCES · SERIES · INDUCTION (assets/seq-lab.js, limits series 3.1–3.2)
========================================================================== */
.sq-flags .lap-row,.sqt-verdict .lap-row{gap:6px}
.sq-tab td,.ic-tab td{font-family:var(--mono);font-size:.82rem}
.sqt-test{background:color-mix(in srgb,var(--signal) 13%,transparent);color:var(--ink-2)}
.sqt-sum{font-size:.95rem;margin-left:4px}
.ic-step .lap-ans{display:grid;gap:2px;overflow-x:auto;overflow-y:hidden;max-width:100%}
.in-check > *,.sq-lab > *,.sq-test > *,.sq-taylor > *,.in-flaw > *{min-width:0;max-width:100%}
.ic-step,.ic-step .lap-ans > *{min-width:0}
.ic-step .hl-p,.lap-help .hl-p,.answer .hl-p{background:color-mix(in srgb,var(--hl-p) 18%,transparent);border-radius:4px;padding:0 .2em}
.ic-tab tr:not(.in) td{color:#c43c3c}
svg.in-dom{display:block;width:100%;height:auto;background:var(--paper);border:1px solid var(--rule);border-radius:12px}
.in-floor{stroke:var(--ink-3);stroke-width:2}
.in-tile rect{fill:var(--card);stroke:var(--ink-2);stroke-width:1.6;transition:fill .2s}
.in-tile{transition:transform .32s cubic-bezier(.5,0,.75,0)}
.in-tile.base rect{stroke:var(--accent);stroke-width:2.2}
.in-tile.down rect{fill:color-mix(in srgb,var(--ok) 55%,var(--card))}
.in-lab{font:10.5px var(--mono);fill:var(--ink-3)}
.in-gap{font:700 16px var(--sans);fill:#c43c3c}
.in-gapl{stroke:#c43c3c;stroke-width:1.4;stroke-dasharray:4 4}
@media (prefers-reduced-motion:reduce){.in-tile{transition:none}}
.fl-claim{margin:2px 0 0}
.fl-lines{margin:4px 0;padding-left:1.6em;display:grid;gap:6px}
.fl-line{display:block;width:100%;text-align:left;font:inherit;color:var(--ink);background:var(--paper);border:1px solid var(--rule);border-radius:10px;padding:8px 12px;cursor:pointer;line-height:1.6}
.fl-line:hover{border-color:var(--ink-3)}
.fl-line.bad{border-color:#c43c3c;background:color-mix(in srgb,#c43c3c 10%,var(--paper))}
.fl-line.wrong{border-color:var(--ink-3);opacity:.7}
.fl-why{border-radius:10px;padding:10px 14px;line-height:1.7}
.fl-why.ok{background:color-mix(in srgb,var(--ok) 13%,transparent)}
.fl-why.no{background:color-mix(in srgb,#d4a017 14%,transparent)}
.proof-tpl{border:1.5px dashed var(--ink-3);border-radius:12px;padding:12px 16px;background:var(--paper);margin:14px 0}
.proof-tpl ol{margin:6px 0 0;padding-left:1.4em;display:grid;gap:6px}
.proof-tpl b.k{color:var(--accent)}
.test-flow{display:grid;gap:8px;grid-template-columns:repeat(auto-fit,minmax(min(100%,230px),1fr));margin:12px 0}
.test-flow > div{border:1px solid var(--rule);border-radius:12px;padding:10px 12px;background:var(--card)}
.test-flow b{display:block;margin-bottom:2px}
.mf-ink{fill:none;stroke:var(--ink);stroke-width:2.4;stroke-linejoin:round}
a.wx-btn{text-decoration:none;display:inline-block}
.in-domino select.lap-in{font:500 .9rem var(--sans)}
/* blog: paired figures + vertical YouTube Shorts facade (added 2026-10-17) */
.post-fig{margin:18px 0;padding:12px;border:1px solid var(--rule);border-radius:12px;background:var(--card)}
.post-fig figcaption{margin-top:8px;font-size:14px;color:var(--ink-2)}
.fig-pair{display:grid;gap:14px}
@media (min-width:640px){.fig-pair{grid-template-columns:1fr 1fr;align-items:end}}
.fig-pair svg.xf{width:100%;height:auto;display:block;max-width:340px;margin:0 auto}
.xf text.xf-big{font:600 18px var(--sans)}
.xf text.xf-lbl{font:600 15px var(--mono)}
.xf text.xf-note{font:12.5px var(--mono);fill:var(--ink-3)}
.screen.short{aspect-ratio:9/16;max-width:340px;margin-inline:auto}
.screen.short .facade h3{font-size:1.35rem}
.lesson .screen .facade p{color:#b4bcc3}
/* ===== AC INDUCTION MOTOR GUIDE (/learn/ac-induction-motor/): figures scripts/acm_figs.py, lab + calculators assets/acm-lab.js ===== */
.acm-lab{border:2px solid var(--signal);border-radius:16px;background:var(--card);padding:12px;margin:18px 0}
.acm-wrap{display:grid;grid-template-columns:minmax(0,300px) minmax(0,1fr);gap:14px}
@media (max-width:900px){.acm-wrap{grid-template-columns:1fr}}
.acm-ctl{display:grid;gap:8px;align-content:start}
.acm-r{display:flex;flex-wrap:wrap;align-items:center;gap:4px 8px;font-size:.86rem;color:var(--ink-2)}
.acm-r[hidden]{display:none}
.acm-r span{flex:1 1 100%;font-weight:600;color:var(--ink)}
.acm-r select{font:inherit;width:100%;padding:5px 8px;border:1px solid var(--rule);border-radius:7px;background:var(--paper);color:var(--ink)}
.acm-r input[type=range]{flex:1;min-width:120px;accent-color:var(--signal)}
.acm-r output{font:600 .82rem var(--mono);min-width:6.5em;text-align:right;color:var(--signal)}
.acm-out{display:grid;gap:8px;align-content:start;min-width:0}
.acm-ch .ee-svg{background:var(--paper)}
.ee-svg .acm-area{fill:color-mix(in srgb,var(--accent) 16%,transparent);stroke:none}
.acm-met dd{font-size:.82rem}
.acm-met{margin:0}
.acm-verdict{margin:0;padding:8px 12px;border-radius:8px;font-weight:600;font-size:.92rem}
.acm-verdict.ok{background:color-mix(in srgb,var(--ok) 12%,var(--card));color:var(--ok)}
.acm-verdict.warn{background:color-mix(in srgb,#d4a017 16%,var(--card));color:color-mix(in srgb,#9a6b00 85%,var(--ink))}
.acm-verdict.bad{background:color-mix(in srgb,#d63b2f 12%,var(--card));color:#c0392b}
.acm-calc .fc-out{background:color-mix(in srgb,var(--accent) 8%,transparent)}
.mc .acm-btns{display:flex;flex-wrap:wrap;gap:6px;margin:8px 0 14px}
.mc .acm-btns button{font:600 .8rem var(--sans);padding:5px 12px;border-radius:999px;border:1px solid var(--signal);background:var(--card);color:var(--signal);cursor:pointer}
.mc .acm-btns button:hover{background:var(--signal);color:#fff}
.mc table.acm-t{font-size:.9rem}
.mc .acm-map{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,230px),1fr));gap:10px;margin:14px 0}
.mc .acm-map a{display:block;border:1px solid var(--rule);border-radius:12px;padding:10px 12px;background:var(--card);text-decoration:none;color:var(--ink)}
.mc .acm-map a:hover{border-color:var(--signal)}
.mc .acm-map b{display:block;color:var(--signal);font-size:.95rem}
.mc .acm-map small{color:var(--ink-3);font-size:.8rem}
@media (max-width:600px){.acm-met,.acm-calc .fc-out{grid-template-columns:1fr;gap:0 10px}.acm-met dd,.acm-calc .fc-out dd{text-align:left;margin:0 0 6px}}
/* ============================================================================
MULTIVARIABLE CALCULUS LABS (assets/mvc-core.js, mvc-lab.js, mvc-vec.js, mvc-eng.js) — /learn/multivariable-calculus/
========================================================================== */
.mv-lab{min-width:0;grid-template-columns:minmax(0,1fr)}
.mv-lab .mv-grid2{display:grid;gap:14px;align-items:start;grid-template-columns:minmax(0,1fr)}
.mv-lab .mv-body,.mv-lab .mv-grid2>*{min-width:0}
.mv-lab textarea,.mv-lab .mv-ta{max-width:100%;width:100%;box-sizing:border-box}
.mv-lab .lap-chips{flex-wrap:wrap}
.mv-lab .lap-lbl{white-space:normal;max-width:100%}
.wx-head h3{max-width:100%;overflow-x:auto;overflow-y:hidden}
@media (min-width:820px){.mv-lab .mv-grid2{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}.mv-lab .mv-grid2.mv-wide-l{grid-template-columns:minmax(0,1.25fr) minmax(0,1fr)}}
.mv-lab .mv-sl2{display:grid;gap:2px 18px;grid-template-columns:minmax(0,1fr)}
@media (min-width:820px){.mv-lab .mv-sl2{grid-template-columns:1fr 1fr}}
.mv-3d{position:relative;min-width:0}
.mv-3d canvas{display:block;width:100%;background:var(--paper);border:1px solid var(--rule);border-radius:12px;touch-action:pan-y;cursor:grab;user-select:none;-webkit-user-select:none}
.mv-3d canvas:active{cursor:grabbing}
.mv-3d canvas:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.mv-3d-tools{display:flex;flex-wrap:wrap;gap:4px;margin-top:6px}
.mv-3d-tools button{font:600 .76rem var(--mono);padding:4px 10px;border-radius:8px;border:1px solid var(--rule);background:var(--paper);color:var(--ink-2);cursor:pointer;min-width:34px}
.mv-3d-tools button:hover{border-color:var(--ink-3);color:var(--ink)}
.mv-3d-tools button.on,.mv-3d-tools button[aria-pressed=true]{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.mv-map{width:100%;height:auto;touch-action:none;user-select:none;-webkit-user-select:none}
.mv-map circle[data-h]{cursor:grab}
.mv-chk{display:flex;flex-wrap:wrap;gap:6px 18px;font-size:.88rem;color:var(--ink-2)}
.mv-chk label{display:inline-flex;gap:6px;align-items:center;cursor:pointer}
.mv-chk input{accent-color:var(--accent)}
.mv-eqs{overflow-x:auto;overflow-y:hidden;max-width:100%}
.mv-eqs .katex-display{margin:.3em 0!important}
.mv-tab{font-size:.84rem}
.mv-tab td{font-family:var(--mono);font-size:.8rem}
.mv-pol svg{width:100%;height:auto}
.mv-out{min-width:0;overflow-x:auto}
.mv-out .lap-ans{margin-top:6px}
.mv-modes{display:flex;flex-wrap:wrap;gap:6px}
.mv-ta{width:100%;min-height:96px;font:500 .9rem var(--mono);padding:8px 10px;border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);resize:vertical}
.mv-note{font-size:.85rem;color:var(--ink-2);margin:2px 0}
.mv-kv{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:6px 12px;font-size:.84rem}
.mv-kv > div{border:1px solid var(--rule);border-radius:9px;padding:6px 10px;background:var(--paper)}
.mv-kv b{display:block;font:500 .72rem var(--mono);color:var(--ink-3);margin-bottom:2px}
.mv-kv span{font:600 .95rem var(--mono);color:var(--ink)}
@media print{.mv-lab{display:none!important}}
.mv-lab .cl-sl{flex-wrap:nowrap}
.mv-lab .cl-sl .lap-lbl{min-width:0;white-space:normal;flex:0 1 auto;max-width:48%}
.mv-lab .cl-sl input[type=range]{flex:1 1 90px;min-width:90px}
.mv-lab .mv-sl2 .cl-sl .lap-lbl{max-width:30%}
.mv-lab .lap-fields .lap-f input{width:110px}
/* ==========================================================================
DC CIRCUITS (lesson 25 · /learn/dc-circuits/): widgets, schematic figures, virtual lab, problem bank.
Everything is scoped under .dcx. Canvas code (assets/dc-core.js, dc-lab.js) reads these tokens from .dcx,
so keep the colours that canvas mixes (--ink-3, --vpos, --vneg) as hex.
========================================================================== */
.dcx{
--sheet:var(--card); --grid-2:#d6cebd; --copper:var(--accent); --copper-2:#f4e0d4; --flow:var(--signal); --flow-2:#dde7f3;
--vpos:#c0582a; --vneg:#5b48b8; --ok-2:#dcefe3; --warn:#8f6400; --warn-2:#f5e9c9; --bad:#ae3434; --bad-2:#f5dcdc;
--s1:#2a78d6; --s2:#eb6834; --s3:#1baf7a; --s4:#eda100; --s5:#e87ba4; --s6:#008300; --s7:#6250d6; --s8:#e34948;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) .dcx{
--grid-2:#2c3843; --copper-2:#3a2519; --flow-2:#1b2d42; --vpos:#e8875a; --vneg:#a796f0; --ok-2:#12301f; --warn:#e3b650; --warn-2:#33280f; --bad:#ef7e7e; --bad-2:#3a1b1b;
--s1:#3987e5; --s2:#d95926; --s3:#199e70; --s4:#c98500; --s5:#d55181; --s6:#008300; --s7:#9085e9; --s8:#e66767}}
:root[data-theme="dark"] .dcx{
--grid-2:#2c3843; --copper-2:#3a2519; --flow-2:#1b2d42; --vpos:#e8875a; --vneg:#a796f0; --ok-2:#12301f; --warn:#e3b650; --warn-2:#33280f; --bad:#ef7e7e; --bad-2:#3a1b1b;
--s1:#3987e5; --s2:#d95926; --s3:#199e70; --s4:#c98500; --s5:#d55181; --s6:#008300; --s7:#9085e9; --s8:#e66767}
.dcx .dc-mono,.dcx .dc-num{font-family:var(--mono);font-variant-numeric:tabular-nums}
.dcx .dc-small,.dcx .small{font-size:.86rem;color:var(--ink-3);margin:0}
.dcx .muted{color:var(--ink-3)}
/* header map */
.dcx .dc-route{list-style:none;padding:0;margin:20px 0 0;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:6px}
.dcx .dc-route li{margin:0}
.dcx .dc-route a{display:flex;align-items:center;gap:8px;padding:7px 9px;border:1px solid var(--rule);border-radius:10px;background:var(--card);text-decoration:none;font-size:.82rem;line-height:1.3;color:var(--ink-2)}
.dcx .dc-route a:hover{border-color:var(--accent);color:var(--ink)}
.dcx .dc-route span{flex:none;width:24px;height:24px;border-radius:50%;border:1.5px solid var(--ink);display:grid;place-items:center;font:600 .72rem/1 var(--mono);color:var(--ink)}
.dcx .dc-route .hot span{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
@media (max-width:720px){.dcx .dc-route{grid-template-columns:repeat(2,minmax(0,1fr))}}
.dcx .dc-facts{display:flex;flex-wrap:wrap;gap:6px;margin:12px 0 0}
.dcx .dc-facts span,.dcx .dc-facts a{font:500 .74rem/1 var(--mono);padding:7px 9px;border:1px solid var(--rule);border-radius:6px;background:var(--paper-2);color:var(--ink-2);text-decoration:none}
.dcx .dc-facts a b{color:var(--accent)}
.dcx .dc-prefix{display:flex;flex-wrap:wrap;gap:6px}
.dcx .dc-prefix span{font:500 .86rem/1 var(--mono);padding:7px 9px;border:1px solid var(--rule);border-radius:6px;background:var(--card)}
.dcx .dc-prefix b{color:var(--accent);margin-right:5px}
/* instruments */
.dcx .dc-inst{border:1.5px solid var(--ink);border-radius:14px;background:var(--card);margin:22px 0;overflow:hidden}
.dcx .dc-inst-h{display:flex;align-items:center;justify-content:space-between;gap:6px 12px;flex-wrap:wrap;padding:9px 16px;border-bottom:1px solid var(--rule);background:var(--paper-2)}
.dcx .dc-inst-h b{font:500 .78rem/1.4 var(--mono);color:var(--accent);letter-spacing:.02em}
.dcx .dc-inst-h > span{font-size:.8rem;color:var(--ink-3)}
.dcx .dc-inst-b{padding:14px 16px;display:grid;grid-template-columns:minmax(0,1fr);gap:12px}
.dcx .dc-inst-b > *{min-width:0}
.dcx .dc-ctl{display:grid;grid-template-columns:7.5rem minmax(0,1fr) 6.5rem;align-items:center;gap:10px;font-size:.9rem}
.dcx .dc-ctl output{font-family:var(--mono);text-align:right;font-variant-numeric:tabular-nums;font-size:.86rem}
@media (max-width:520px){.dcx .dc-ctl{grid-template-columns:5.6rem minmax(0,1fr) 5.4rem;gap:6px}}
.dcx input[type=range]{width:100%;accent-color:var(--accent)}
.dcx .dc-readout{display:grid;grid-template-columns:repeat(auto-fit,minmax(9rem,1fr));gap:8px}
.dcx .dc-readout div{border:1px solid var(--rule);border-radius:8px;padding:8px 10px;background:var(--paper)}
.dcx .dc-readout small{display:block;font-size:.76rem;color:var(--ink-3)}
.dcx .dc-readout b{font:600 1.05rem/1.3 var(--mono);font-variant-numeric:tabular-nums}
.dcx .dc-readout b.hl{color:var(--accent)}
.dcx .dc-wplot-box{position:relative;min-width:0;overflow:hidden}
.dcx .dc-wplot{width:100%;display:block}
.dcx .dc-wtip,.dcx .dc-tip,.dcx .dc-ptip{position:absolute;pointer-events:none;background:var(--ink);color:var(--paper);font:500 .74rem/1.5 var(--mono);padding:5px 8px;border-radius:6px;white-space:nowrap;z-index:5}
.dcx .dc-legend{display:flex;flex-wrap:wrap;gap:6px 16px;font-size:.8rem;color:var(--ink-2)}
.dcx .dc-legend i{display:inline-block;width:14px;height:3px;border-radius:2px;margin-right:6px;vertical-align:.25em}
.dcx .dc-seg{display:inline-flex;border:1px solid var(--ink);border-radius:8px;overflow:hidden;background:var(--card)}
.dcx .dc-seg button{font:500 .86rem/1 var(--sans);background:none;color:var(--ink);border:0;padding:8px 12px;cursor:pointer}
.dcx .dc-seg button+button{border-left:1px solid var(--ink)}
.dcx .dc-seg button.on{background:var(--ink);color:var(--paper)}
.dcx .dc-resistor{width:100%;max-width:360px;height:auto;margin:0 auto}
.dcx .dc-cc-sel{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:8px}
.dcx .dc-cc-sel label{display:grid;gap:3px;font-size:.76rem;color:var(--ink-3)}
@media (max-width:560px){.dcx .dc-cc-sel{grid-template-columns:1fr 1fr}}
.dcx select,.dcx input[type=text],.dcx textarea{font:inherit;font-size:.88rem;color:var(--ink);background:var(--paper);border:1px solid var(--rule);border-radius:6px;padding:6px 8px;min-width:0}
.dcx select:focus,.dcx input[type=text]:focus{border-color:var(--signal);outline:none}
.dcx .dc-tbl-wrap{overflow-x:auto;border:1px solid var(--rule);border-radius:10px;background:var(--card)}
.dcx .dc-tbl{border-collapse:collapse;width:100%;font-size:.88rem;min-width:30rem}
.dcx .dc-tbl th,.dcx .dc-tbl td{padding:7px 10px;text-align:left;border-bottom:1px solid var(--rule)}
.dcx .dc-tbl thead th{font:500 .74rem/1.4 var(--mono);color:var(--ink-3);background:var(--paper-2)}
.dcx .dc-tbl tr:last-child td{border-bottom:0}
.dcx .dc-tbl .dc-num{text-align:right;white-space:nowrap}
.dcx .dc-tbl tr.on td{background:var(--flow-2)}
.dcx .dc-tbl tr[data-id]{cursor:pointer}
.dcx .dc-tbl td.src{color:var(--accent);font-weight:600}
.dcx .dc-fig{margin:12px 0;overflow-x:auto;text-align:center}
.dcx .dc-fig canvas{display:inline-block;max-width:none}
.dcx .dc-fig svg{display:inline-block}
.dcx .dc-fig figcaption{font-size:.82rem;color:var(--ink-3)}
/* technology cards */
.dcx .dc-tech{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:18px 0}
@media (max-width:640px){.dcx .dc-tech{grid-template-columns:minmax(0,1fr)}}
.dcx .dc-tc{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:14px 16px;display:flex;flex-direction:column;gap:4px}
.dcx .dc-ey{font:500 .72rem/1.4 var(--mono);color:var(--accent);letter-spacing:.04em;text-transform:uppercase}
.dcx .dc-big{font:600 1.35rem/1.2 var(--mono);color:var(--ink)}
.dcx .dc-tc h3{margin:2px 0 0;font-size:1rem}
.dcx .dc-tc p{margin:0;font-size:.88rem;color:var(--ink-2)}
.dcx .dc-tc .dc-link{margin-top:auto;padding-top:8px;border-top:1px dashed var(--rule);font-size:.8rem;color:var(--ink-3)}
.dcx .dc-tc a{color:var(--signal)}
/* virtual lab band */
.dc-band{background:var(--card);border-block:1.5px solid var(--ink);padding:40px 0 48px;margin:8px 0 0;scroll-margin-top:70px}
.dc-band-head{display:flex;flex-wrap:wrap;align-items:flex-end;justify-content:space-between;gap:12px 20px;margin-bottom:16px}
.dc-band-head p:not(.eyebrow){max-width:62ch;margin:8px 0 0;color:var(--ink-2)}
.dc-band h3{font-size:1.25rem;margin:32px 0 12px}
.dcx .dc-tools{display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center;padding:8px;border:1.5px solid var(--ink);border-bottom:0;border-radius:12px 12px 0 0;background:var(--paper)}
.dcx .dc-tg{display:flex;gap:4px;flex-wrap:wrap;align-items:center}
.dcx .dc-tg+.dc-tg{padding-left:12px;border-left:1px solid var(--rule)}
@media (max-width:640px){.dcx .dc-tg+.dc-tg{padding-left:0;border-left:0}}
.dcx .dc-tool{display:inline-flex;align-items:center;gap:5px;font:500 .8rem/1 var(--sans);color:var(--ink);background:var(--card);border:1px solid var(--rule);border-radius:6px;padding:6px 8px;cursor:pointer;min-height:34px}
.dcx .dc-tool svg{width:22px;height:16px;flex:none;stroke:currentColor;fill:none;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.dcx .dc-tool:hover{border-color:var(--ink-3)}
.dcx .dc-tool.on,.dcx #lab-dep.on{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.dcx .dc-tool:disabled{opacity:.4;cursor:default}
.dcx .dc-toast{font-size:.78rem;color:var(--ok)}
.dcx .dc-sub{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center;padding:6px 10px;border:1.5px solid var(--ink);border-bottom:0;font-size:.8rem;color:var(--ink-2);background:var(--card)}
.dcx .dc-sub label{display:inline-flex;align-items:center;gap:5px;cursor:pointer}
.dcx .dc-hint{margin-left:auto;color:var(--ink-3)}
.dcx .dc-main{display:grid;grid-template-columns:minmax(0,1fr) 18rem;border:1.5px solid var(--ink);border-radius:0 0 12px 12px;overflow:hidden}
@media (max-width:980px){.dcx .dc-main{grid-template-columns:minmax(0,1fr)}.dcx .dc-side{border-left:0!important;border-top:1px solid var(--ink)}}
.dcx .dc-wrap{position:relative;overflow:auto;background:var(--card);max-height:78vh;min-width:0}
.dcx #lab-cv{display:block;touch-action:none;outline:none}
.dcx .dc-side{border-left:1px solid var(--ink);padding:12px 14px;font-size:.88rem;background:var(--paper);min-width:0}
.dcx .side-h{font:500 .74rem/1.4 var(--mono);letter-spacing:.04em;color:var(--ink-3);margin:12px 0 6px}
.dcx .side-h:first-child{margin-top:0}
.dcx .side-h .muted{font-family:var(--sans);letter-spacing:0}
.dcx .kv{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:3px 10px;margin:0}
.dcx .kv dt{color:var(--ink-3)}
.dcx .kv dd{margin:0;text-align:right;font-family:var(--mono);font-variant-numeric:tabular-nums}
.dcx .howto{padding-left:18px;margin:4px 0;color:var(--ink-2)}
.dcx .howto li{margin:4px 0}
.dcx .fld{display:grid;gap:3px;margin:8px 0}
.dcx .fld span{font-size:.76rem;color:var(--ink-3)}
.dcx .fld em{font-style:normal;font-family:var(--mono)}
.dcx .fld input,.dcx .fld select{width:100%}
.dcx .err{color:var(--bad)}
.dcx .dc-btn{font:500 .86rem/1 var(--sans);color:var(--ink);background:var(--card);border:1px solid var(--ink);border-radius:8px;padding:8px 12px;cursor:pointer;min-height:36px}
.dcx .dc-btn:hover{background:var(--flow-2)}
.dcx .dc-btn.pri{background:var(--ink);color:var(--paper)}
.dcx .dc-btn.pri:hover{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.dcx .dc-btn.danger{color:var(--bad);border-color:var(--bad)}
.dcx .dc-btn.ghost{border-color:var(--rule)}
.dcx .dc-btnrow{display:flex;flex-wrap:wrap;gap:6px;margin:10px 0}
.dcx .tag-src{font:600 .68rem/1 var(--sans);color:var(--accent);border:1px solid currentColor;border-radius:4px;padding:2px 4px}
.dcx .dc-status{font-size:.88rem;color:var(--ink-2);padding:10px 0;line-height:1.9}
.dcx .pill{display:inline-block;font:600 .7rem/1 var(--mono);padding:4px 7px;border-radius:99px;vertical-align:.08em}
.dcx .pill.ok{background:var(--ok-2);color:var(--ok)}
.dcx .pill.warn{background:var(--warn-2);color:var(--warn)}
.dcx .pill.bad{background:var(--bad-2);color:var(--bad)}
.dcx .dc-tran{border:1px solid var(--rule);border-radius:12px;padding:12px;margin:6px 0 16px;background:var(--paper);position:relative}
.dcx .dc-tran-ctl{display:flex;flex-wrap:wrap;align-items:center;gap:8px 14px;font-size:.88rem}
.dcx .dc-tran-ctl input[type=text]{width:6.5rem;font-family:var(--mono)}
.dcx .dc-tran-ctl input[type=range]{flex:1 1 12rem}
.dcx #lab-time{font-family:var(--mono);font-variant-numeric:tabular-nums;min-width:11rem;font-size:.86rem}
.dcx #lab-tran-note{margin:6px 0 0}
.dcx .dc-plots{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:10px}
@media (max-width:860px){.dcx .dc-plots{grid-template-columns:minmax(0,1fr)}}
.dcx .dc-plot-box{background:var(--card);border:1px solid var(--rule);border-radius:8px;padding:6px;min-width:0}
.dcx .dc-plot-box canvas{display:block;touch-action:pan-y}
.dcx .dc-tchips{display:flex;flex-wrap:wrap;gap:4px;padding:5px 3px 0}
.dcx .tchip{font:500 .72rem/1 var(--mono);background:none;border:1px solid var(--rule);border-radius:99px;padding:5px 8px;color:var(--ink-3);cursor:pointer}
.dcx .tchip.on{color:var(--ink);border-color:var(--ink-3)}
.dcx .tchip i{display:inline-block;width:9px;height:9px;border-radius:50%;border:2px solid;margin-right:5px;vertical-align:-.05em}
.dcx .dc-tabs{display:flex;gap:3px;border-bottom:1.5px solid var(--ink);margin-top:10px}
.dcx .dc-tabs button{font:500 .88rem/1 var(--sans);background:none;border:1.5px solid transparent;border-bottom:0;border-radius:8px 8px 0 0;padding:10px 14px;cursor:pointer;color:var(--ink-2);margin-bottom:-1.5px}
.dcx .dc-tabs button.on{background:var(--card);border-color:var(--ink);color:var(--ink);font-weight:600}
.dcx .lab-pane{padding-top:8px}
.dcx .lab-pane .dc-tbl-wrap{margin:10px 0}
.dcx .balance{font-size:.86rem;color:var(--ink-2)}
.dcx .dc-chips{display:flex;flex-wrap:wrap;gap:5px}
.dcx .dc-chip{font-size:.76rem;padding:5px 8px;border:1px solid var(--rule);border-radius:6px;background:var(--paper)}
.dcx .mna{border-collapse:collapse;font:500 .78rem/1.3 var(--mono);font-variant-numeric:tabular-nums;background:var(--card)}
.dcx .mna th,.dcx .mna td{padding:5px 8px;text-align:right;border-bottom:1px solid var(--grid-2)}
.dcx .mna thead th{color:var(--accent);font-weight:600}
.dcx .mna tbody th{text-align:left;color:var(--ink-3);font-family:var(--sans);font-weight:500;white-space:nowrap}
.dcx .mna tr.sep td,.dcx .mna tr.sep th{border-top:2px solid var(--ink-3)}
.dcx .mna td.eq{color:var(--ink-3);text-align:center}
.dcx .mna .z{color:var(--grid-2)}
.dcx .dc-io{margin:8px 0;display:grid;gap:6px}
.dcx .dc-io textarea{width:100%;min-height:5rem;font:400 .75rem/1.4 var(--mono)}
.dcx .dc-exps{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}
@media (max-width:1000px){.dcx .dc-exps{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:640px){.dcx .dc-exps{grid-template-columns:minmax(0,1fr)}}
.dcx .dc-exp{border:1px solid var(--rule);border-radius:12px;padding:12px 14px;background:var(--paper);display:flex;flex-direction:column;gap:4px;font-size:.88rem}
.dcx .dc-exp h4{margin:0;font:600 1rem/1.35 var(--serif)}
.dcx .dc-exp ol{padding-left:18px;margin:4px 0 8px;color:var(--ink-2)}
.dcx .dc-exp .dc-btn{margin-top:auto;align-self:flex-start}
/* problem bank */
.dcx .dc-lvlbars{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:8px;margin:14px 0}
@media (max-width:640px){.dcx .dc-lvlbars{grid-template-columns:repeat(2,minmax(0,1fr))}}
.dcx .lvlbar{border:1px solid var(--rule);border-radius:10px;padding:8px 10px;background:var(--card);font-size:.76rem}
.dcx .lvlbar .lvl{white-space:normal}
.dcx .lvlbar .bar{height:6px;background:var(--paper-2);border-radius:3px;margin-top:6px;overflow:hidden}
.dcx .lvlbar .bar i{display:block;height:100%;background:var(--ok);width:0}
.dcx .lvl{display:inline-flex;align-items:center;gap:6px;font:500 .72rem/1.3 var(--mono);color:var(--ink-2);white-space:nowrap}
.dcx .lvl svg{width:34px;height:12px;flex:none}
.dcx .dc-pb-head{display:flex;flex-wrap:wrap;gap:8px 16px;align-items:center;justify-content:space-between;margin:10px 0}
.dcx .dc-filters{display:flex;flex-wrap:wrap;gap:5px}
.dcx .dc-filters button{font:500 .86rem/1 var(--sans);background:var(--card);border:1px solid var(--rule);border-radius:99px;padding:7px 12px;cursor:pointer;color:var(--ink-2)}
.dcx .dc-filters button.on{background:var(--ink);color:var(--paper);border-color:var(--ink)}
.dcx .prob{border:1px solid var(--rule);border-radius:14px;background:var(--card);margin:14px 0;overflow:hidden;scroll-margin-top:80px}
.dcx .prob > header{display:flex;flex-wrap:wrap;align-items:center;gap:6px 12px;padding:10px 16px;border-bottom:1px solid var(--rule);background:var(--paper-2)}
.dcx .prob > header h4{margin:0;font:600 1rem/1.4 var(--serif);flex:1 1 14rem}
.dcx .prob .topic{font-size:.76rem;color:var(--ink-3)}
.dcx .prob .done{font:600 .72rem/1 var(--mono);color:var(--ok);background:var(--ok-2);padding:5px 8px;border-radius:99px}
.dcx .prob .bd{padding:6px 16px 14px}
.dcx .prob .bd > p{margin:8px 0}
.dcx .ans{display:grid;gap:8px;margin:12px 0}
.dcx .ans-row{display:grid;grid-template-columns:minmax(6rem,auto) minmax(0,10rem) auto 1fr;align-items:center;gap:8px;font-size:.9rem}
.dcx .ans-row input{font-family:var(--mono);width:100%}
.dcx .ans-row .u{font-family:var(--mono);color:var(--ink-3)}
.dcx .ans-row .fb{font-size:.8rem}
.dcx .fb.ok{color:var(--ok)} .dcx .fb.no{color:var(--bad)}
@media (max-width:520px){.dcx .ans-row{grid-template-columns:minmax(0,1fr) 7rem auto}.dcx .ans-row .fb{grid-column:1/-1}}
.dcx .dc-tag{display:inline-block;font:500 .68rem/1 var(--mono);color:var(--accent);border:1px solid currentColor;padding:3px 5px;border-radius:4px;margin-right:6px;vertical-align:.1em}
.dcx .sol{border-top:1px dashed var(--rule);margin-top:8px;padding-top:4px}
.dcx .sol summary{cursor:pointer;font-weight:600;font-size:.9rem;padding:6px 0;color:var(--signal)}
.dcx .sol p{margin:8px 0}
.dcx .dc-gen .dc-inst-b{gap:8px}
.dcx .dc-streak{font:500 .8rem/1 var(--mono);color:var(--ink-2)}
.dcx .dc-streak b{color:var(--accent)}
/* study path */
.dcx .dc-stage{display:grid;grid-template-columns:2.6rem minmax(0,1fr);gap:12px;padding:14px 0;border-bottom:1px solid var(--rule)}
.dcx .dc-stage .n{font:700 1.6rem/1 var(--serif);color:var(--accent)}
.dcx .dc-stage h3{margin:0 0 4px;font-size:1.02rem}
.dcx .dc-stage p{margin:4px 0;font-size:.92rem;color:var(--ink-2)}
/* ===== STAR–DELTA ANALYSIS (/learn/motor-control/star-delta-analysis/, /blog/star-delta-timer-setting/): engine assets/yd-core.js, labs assets/yd-lab.js, figures scripts/yd_figs.py ===== */
.yd-lab,.yd-sweep,.yd-run{border:2px solid var(--signal);border-radius:16px;background:var(--card);padding:12px;margin:18px 0}
.yd-lab .acm-wrap,.yd-sweep .acm-wrap,.yd-run .acm-wrap{grid-template-columns:minmax(0,1fr)}
.yd-lab .acm-ctl,.yd-sweep .acm-ctl,.yd-run .acm-ctl{grid-template-columns:repeat(auto-fill,minmax(min(100%,230px),1fr));gap:8px 16px}
.yd-lab .acm-ctl .pv-note,.yd-sweep .acm-ctl .pv-note,.yd-run .acm-ctl .pv-note,.yd-lab .yd-btns,.yd-sweep .yd-btns{grid-column:1/-1}
.yd-lab .acm-met{grid-template-columns:minmax(0,1.1fr) minmax(0,1fr)}
.yd-btns{display:flex;flex-wrap:wrap;gap:6px}
.yd-btns button,.yd-sc button{font:600 .8rem var(--sans);padding:6px 12px;border-radius:999px;border:1px solid var(--signal);background:var(--card);color:var(--signal);cursor:pointer}
.yd-btns button:hover,.yd-sc button:hover{background:var(--signal);color:#fff}
.yd-sc{display:flex;flex-wrap:wrap;gap:6px;margin:8px 0 14px}
.yd-rec{margin:0;padding:8px 12px;border-radius:8px;background:color-mix(in srgb,var(--accent) 10%,var(--card));font-size:.9rem}
.yd-tab{overflow-x:auto;max-width:100%}
table.yd-t{font-size:.82rem;min-width:420px}
table.yd-t td,table.yd-t th{padding:4px 8px;white-space:nowrap}
table.yd-t td{font-family:var(--mono);font-size:.78rem}
.yd-key{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,250px),1fr));gap:10px;margin:14px 0}
.yd-key div{border:1px solid var(--rule);border-left:4px solid var(--signal);border-radius:10px;padding:10px 12px;background:var(--card)}
.yd-key b{display:block;font-size:.95rem;color:var(--ink)}
.yd-key span{display:block;font:600 1.25rem var(--mono);color:var(--signal);margin:2px 0}
.yd-key small{color:var(--ink-3);font-size:.8rem;line-height:1.45;display:block}
.yd-tl{list-style:none;margin:14px 0;padding:0 0 0 18px;border-left:3px solid var(--rule)}
.yd-tl li{position:relative;margin:0 0 14px;padding-left:6px}
.yd-tl li::before{content:"";position:absolute;left:-26px;top:.35em;width:13px;height:13px;border-radius:50%;background:var(--card);border:3px solid var(--signal)}
.yd-tl li.now::before{background:var(--signal)}
.yd-tl li.fut::before{border-style:dashed;border-color:var(--accent)}
.yd-tl b.yr{font:600 .85rem var(--mono);color:var(--signal);margin-right:6px}
.yd-abs{border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:12px 16px;margin:14px 0}
.yd-abs p{margin:.4em 0}
.yd-abs .kw{font-size:.86rem;color:var(--ink-3)}
@media (max-width:600px){.yd-lab,.yd-sweep,.yd-run{padding:8px}}
/* ==========================================================================
SEQUENCES & SERIES CHAPTER (chapter 26, /learn/sequences-and-series/): labs assets/series-lab.js, figures scripts/sr_figs.py
========================================================================== */
.sr-lab{gap:10px}
.sr-lab .lap-eq{font-size:.95rem}
.sr-two{display:grid;gap:12px;min-width:0}
@media (min-width:760px){.sr-two{grid-template-columns:minmax(0,1.45fr) minmax(0,1fr);align-items:start}}
.sr-two > *{min-width:0}
svg.sr-cplane{max-width:340px;margin:0 auto}
.sr-lab .mk-plot{max-height:60vh}
@media (max-width:640px){
.sr-lab{padding:12px 10px}
.sr-pre,.sr-modes{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:thin;padding-bottom:4px;margin-inline:-2px}
.sr-pre > .lap-chip,.sr-modes > .lap-chip{flex:0 0 auto}
svg.sr-cplane{max-width:250px}
.sr-lab .lap-pt{font-size:.8rem}
.sr-lab .lap-pt td,.sr-lab .lap-pt th{padding:4px 5px}
.sr-lab .lap-eq{font-size:.86rem}
}
.sr-lab .table-wrap{overflow-x:auto;margin:0}
.sr-qs{border:1px dashed var(--rule);border-radius:12px;padding:6px 12px;background:var(--paper);overflow-x:auto;min-height:70px}
.sr-qs .lv{float:right;margin-top:6px}
.sr-qs .katex-display,.sr-dq .katex-display,.sr-lab .lap-eq .katex-display{background:none;box-shadow:none;border:0}
.sr-qh{margin:4px 0 0;font:600 .85rem var(--sans);color:var(--ink-2)}
.lap-chip.good{border-color:var(--ok);background:color-mix(in srgb,var(--ok) 18%,var(--paper));color:var(--ink)}
.lap-chip.bad{border-color:#c43c3c;background:color-mix(in srgb,#c43c3c 14%,var(--paper));color:var(--ink)}
.lap-chip.on.good,.lap-chip.on.bad{color:var(--ink)}
.sr-score{margin-left:auto;color:var(--ink-2)}
.sr-dq{border:1px solid var(--rule);border-radius:12px;padding:8px 14px;background:var(--paper);overflow-x:auto}
.sr-dq p{margin:6px 0}
.sr-tag{cursor:default;font-size:.72rem;padding:2px 9px}
.sr-code{margin:6px 0;padding:10px 12px;background:var(--paper);border:1px solid var(--rule);border-radius:10px;overflow-x:auto;font:.76rem/1.5 var(--mono);color:var(--ink)}
.sr-lc,.sr-lr{display:flex;flex-wrap:wrap;align-items:center;gap:6px 8px}
.sr-lc:empty{display:none}
.sr-side .lap-pt{margin:4px 0}
/* lesson-page helpers used by the chapter */
.sr-map{display:grid;gap:8px;grid-template-columns:repeat(auto-fit,minmax(min(100%,200px),1fr));margin:14px 0}
.sr-map a{display:block;text-decoration:none;border:1px solid var(--rule);border-radius:12px;padding:10px 12px;background:var(--card)}
.sr-map a:hover{border-color:var(--ink-3)}
.sr-map b{display:block;font-family:var(--serif)}
.sr-map span{font-size:.86rem;color:var(--ink-2)}
.sr-map .mono{color:var(--accent);font-size:.72rem}
.sr-exam{border-left:4px solid var(--signal);background:color-mix(in srgb,var(--signal) 7%,transparent);border-radius:0 12px 12px 0;padding:10px 14px;margin:14px 0}
.sr-exam > b{display:block;margin-bottom:4px}
.sr-trap{border-left:4px solid #c43c3c;background:color-mix(in srgb,#c43c3c 7%,transparent);border-radius:0 12px 12px 0;padding:10px 14px;margin:14px 0}
.sr-trap > b{display:block;margin-bottom:4px;color:#c43c3c}
.sr-q{border:1px solid var(--rule);border-radius:12px;background:var(--card);margin:10px 0;padding:0}
.sr-q > summary{cursor:pointer;padding:10px 14px;list-style:none;display:flex;gap:10px;align-items:baseline}
.sr-q > summary::-webkit-details-marker{display:none}
.sr-q > summary .mono{color:var(--accent);flex:0 0 auto}
.sr-q > summary .sr-qt{flex:1 1 auto;min-width:0;overflow-x:auto}
.sr-q > summary::after{content:"เฉลย ▾";font:500 .75rem var(--sans);color:var(--ink-3);flex:0 0 auto}
.sr-q[open] > summary::after{content:"ซ่อน ▴"}
.sr-q > div{padding:0 14px 12px;border-top:1px dashed var(--rule)}
.sr-q .answer{margin-top:8px}
.home-sr .sr-chips a{white-space:nowrap}
svg.mf.sr-fig{max-width:560px;margin:0 auto}
.mf-arrowh{fill:var(--ink-3);stroke:none}
.sr-fig .mf-box{fill:var(--card)}
/* ===== HOME: latest-updates box ( from data/updates.json, live refresh in assets/home.js) + /updates/ page ===== */
.home-updates{padding-top:26px;padding-bottom:6px}
.hu-head{display:flex;flex-wrap:wrap;align-items:flex-end;justify-content:space-between;gap:10px 16px;margin-bottom:14px}
.hu-head h2{font-size:clamp(1.35rem,3vw,1.9rem)}
.hu-head .eyebrow{margin-bottom:6px}
.hu-list{list-style:none;margin:0;padding:0;display:grid;gap:10px}
@media (min-width:860px){.hu-list{grid-template-columns:1.3fr 1fr 1fr}.hu-top{grid-row:span 2}}
.hu-item{border:1px solid var(--rule);border-radius:14px;background:var(--card);padding:12px 14px;display:flex;flex-direction:column;gap:6px;min-width:0}
.hu-top{border-color:color-mix(in srgb,var(--accent) 45%,var(--rule));background:linear-gradient(135deg,color-mix(in srgb,var(--accent) 10%,var(--card)),var(--card) 62%);box-shadow:var(--shadow)}
.hu-meta{display:flex;flex-wrap:wrap;align-items:center;gap:6px 8px;font-size:.8rem;color:var(--ink-3)}
.hu-ic{font-size:1rem;line-height:1}
.hu-new{font:600 .68rem var(--mono);background:var(--accent);color:#fff;border-radius:999px;padding:1px 8px;letter-spacing:.04em}
.hu-text{margin:0;font-size:.92rem;line-height:1.6;color:var(--ink-2);display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden;cursor:pointer}
.hu-top .hu-text{-webkit-line-clamp:7;color:var(--ink);font-size:.98rem}
.hu-item.open .hu-text{-webkit-line-clamp:unset;display:block}
.hu-link{margin-top:auto;font-size:.88rem;color:var(--signal);text-decoration:none;font-weight:600}
.hu-sub{margin:4px 0 0;font-size:.9rem;color:var(--ink-2)}
.hu-chips{display:flex;flex-wrap:wrap;gap:6px;margin:2px 0}
.hu-chips a{font-size:.8rem;line-height:1.3;padding:4px 10px;border-radius:999px;border:1px solid color-mix(in srgb,var(--signal) 35%,var(--rule));background:color-mix(in srgb,var(--signal) 7%,var(--card));color:var(--ink);text-decoration:none}
.hu-chips a:hover{border-color:var(--signal);color:var(--signal)}
.hu-top .hu-chips a{border-color:color-mix(in srgb,var(--accent) 40%,var(--rule));background:color-mix(in srgb,var(--accent) 8%,var(--card))}
.post .hu-chips{margin:8px 0}
.hu-link:hover{text-decoration:underline}
@media (max-width:640px){.hu-list .hu-item:nth-child(n+5){display:none}.hu-head .btn{width:100%;justify-content:center}}
.upd-page .feed-wrap{max-width:820px}
/* ==========================================================================
SOLUTIONS (/solutions/) — one worked problem per page, shared from Facebook/LINE/X
The problem box uses the same dark card as the share image so a reader arriving from a post sees the same thing.
========================================================================== */
.sol-page{--hl-f:#f2b705;--hl-p:#2a78d6;--hl-u:#1baf7a;--hl-c:#9b5de5;--red:#e0352b}
.sol-problem{position:relative;overflow:hidden;margin:22px 0 0;padding:20px 22px 18px 28px;border-radius:16px;color:#ece8df;
background-color:#172029;background-image:linear-gradient(rgba(236,232,223,.05) 1px,transparent 1px),linear-gradient(90deg,rgba(236,232,223,.05) 1px,transparent 1px);background-size:26px 26px;
box-shadow:inset 0 0 0 1px rgba(236,232,223,.08),var(--shadow)}
.sol-problem::before{content:"";position:absolute;left:0;top:0;bottom:0;width:8px;background:#e8692c}
.sol-problem a{color:#f5a275}
.sp-label{display:block;font-size:.78rem;color:#f07a3e;letter-spacing:.03em}
.sol-problem .sp-text{margin:8px 0 0;color:#cdd3d8;max-width:66ch}
.sp-math{overflow-x:auto;overflow-y:hidden;color:#fff;-webkit-overflow-scrolling:touch}
.sp-math .katex-display{margin:.45em 0 .35em;font-size:1.85em}
.sp-ans{margin:4px 0 0;border:1px dashed rgba(236,232,223,.28);border-radius:12px;background:rgba(255,255,255,.03)}
.sp-ans summary{cursor:pointer;padding:9px 14px;font-weight:600;color:#ece8df;list-style:none}
.sp-ans summary::-webkit-details-marker{display:none}
.sp-ans summary::before{content:"▸ ";color:#f07a3e}
.sp-ans[open] summary::before{content:"▾ "}
.sp-ans summary small{font-weight:400;color:#8a949c}
.sp-ans > div{overflow-x:auto;padding:0 14px 6px;color:#fff}
.sp-ans .katex-display{margin:.3em 0 .6em;font-size:1.25em}
.sp-meta{display:flex;flex-wrap:wrap;gap:4px 18px;margin-top:14px;font:500 .78rem var(--mono);color:#8a949c}
.sp-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}
.sol-problem .btn-ghost{background:transparent;border-color:rgba(236,232,223,.25);color:#ece8df}
.sol-problem .btn-ghost:hover,.sol-problem .btn-ghost[aria-pressed="true"]{border-color:#f07a3e;color:#f5a275}
.lv-dots{color:#e8692c;letter-spacing:.08em}
.share.share-top{margin-top:14px}
.sol-fig .xf-h{font-size:13.5px}
@media (max-width:600px){
.sol-problem{padding:16px 14px 14px 20px}
.sp-math .katex-display{font-size:1.35em}
}
/* hub and cards */
.sol-chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:22px}
.sol-chips a{display:inline-flex;align-items:center;gap:8px;padding:7px 14px;border:1px solid var(--rule);border-radius:999px;background:var(--card);color:var(--ink);text-decoration:none;font-weight:600;font-size:.9rem}
.sol-chips a span{font-family:var(--serif);color:var(--accent)}
.sol-chips a small{font:500 .74rem var(--mono);color:var(--ink-3)}
.sol-chips a:hover{border-color:var(--accent)}
.sol-topic + .sol-topic{margin-top:44px}
.sol-topic-head{display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:6px 16px;margin-bottom:14px}
.sol-topic-head h2{margin:0;scroll-margin-top:90px}
.sol-topic-head h2 small{font:500 .8rem var(--mono);color:var(--ink-3);margin-left:6px}
.sol-topic-head .mono{font-size:.8rem;color:var(--ink-3)}
.sol-sym{display:inline-grid;place-items:center;min-width:1.7em;height:1.7em;padding:0 .3em;margin-right:10px;border-radius:9px;background:var(--ink);color:var(--paper);font-size:.85em;vertical-align:.08em}
.sol-grid{display:grid;gap:14px}
@media (min-width:700px){.sol-grid{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1050px){.sol-grid{grid-template-columns:repeat(3,1fr)}}
.sol-card{display:flex;flex-direction:column;gap:10px;min-width:0;text-decoration:none;background:var(--card);border:1px solid var(--rule);border-radius:14px;padding:16px 18px 14px;
transition:transform .18s,border-color .18s,box-shadow .18s}
.sol-card:hover{transform:translateY(-3px);border-color:var(--accent);box-shadow:var(--shadow)}
.sc-top{display:flex;justify-content:space-between;gap:8px;font-size:.74rem}
.sc-no{color:var(--accent);font-weight:600}
.sc-lv{color:var(--ink-3)}
.sc-math{display:block;overflow-x:auto;overflow-y:hidden;padding:4px 10px;border-radius:10px;color:#fff;
background-color:#172029;background-image:linear-gradient(rgba(236,232,223,.05) 1px,transparent 1px),linear-gradient(90deg,rgba(236,232,223,.05) 1px,transparent 1px);background-size:20px 20px}
.sc-math .katex-display{margin:.55em 0;font-size:1.25em}
.sol-card b{font-size:1.04rem;line-height:1.45;color:var(--ink)}
.sc-tech{align-self:flex-start;font-size:.72rem;color:var(--signal);border:1px solid var(--rule);border-radius:999px;padding:2px 10px}
.sc-foot{display:flex;justify-content:space-between;gap:10px;margin-top:auto;padding-top:4px;font-family:var(--mono);font-size:.76rem;color:var(--ink-3)}
.sc-go{color:var(--accent)}
.sol-how{max-width:70ch;padding-left:1.3em}
.sol-how li{margin-bottom:10px;color:var(--ink-2)}
.sol-how b{color:var(--ink)}
.sol-more-h{font-size:1.25rem}
.sol-box{border-left-color:var(--accent)}
@media print{.sp-actions,.share-top{display:none!important}.sp-ans > div{display:block}}
/* dark math panels: the phone scroll cue on .katex-display fades into var(--card), so give it the panel colour */
.sp-math,.sc-math{--card:#172029}
.sp-ans{--card:#1b252e}
/* ==========================================================================
LINEAR ALGEBRA 7.10–7.12 (2026-10-25): rank, numerical methods, exam practice — labs in assets/la-num.js
========================================================================== */
.ln-lab{gap:12px}
.ln-lab .mk-plot{touch-action:pan-y;max-height:62vh}
.ln-scroll{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:thin;padding-bottom:4px}
.ln-scroll > .lap-chip{flex:0 0 auto}
.ln-ta-l{display:grid;gap:4px;min-width:0}
.ln-ta-l .lap-lbl{white-space:normal}
.ln-ta{font:500 .95rem/1.5 var(--mono);resize:vertical;min-height:5.5em;width:100%;box-sizing:border-box}
.ln-chk{display:inline-flex;align-items:center;gap:6px;font-size:.88rem;color:var(--ink-2);cursor:pointer}
.ln-chk input{width:18px;height:18px;accent-color:var(--accent)}
.ln-res{display:flex;flex-wrap:wrap;gap:12px 22px;align-items:flex-start}
.ln-res-mx{display:flex;flex-direction:column;gap:6px;min-width:0;max-width:100%;overflow-x:auto}
.ln-res-mx > .mono{font-size:.74rem;color:var(--ink-3)}
.ln-res-mx > .mxv{align-self:flex-start}
.lesson .ln-big,.ln-big{margin:2px 0;font:500 1.02rem var(--mono);color:var(--ink)}
.ln-big b{color:var(--accent);font-size:1.12em}
.ln-sol{display:flex;flex-wrap:wrap;align-items:center;gap:8px 10px;margin:6px 0;overflow-x:auto}
.ln-sol > .mono{font-size:.82rem;color:var(--ink-2)}
.mxv > span.zr{opacity:.45}
.mxv > span.hr{background:color-mix(in srgb,var(--accent) 14%,transparent)}
.ln-ab[hidden],.ln-eps[hidden]{display:none}
.ln-3d-wrap{min-width:0}
svg.ln-3d{display:block;width:100%;max-width:400px;height:auto;margin:0 auto;background:var(--paper);border:1px solid var(--rule);border-radius:10px;touch-action:pan-y;cursor:grab;user-select:none;-webkit-user-select:none}
svg.ln-3d:active{cursor:grabbing}
.ln-3d-ctl .lap-row{gap:4px 8px}
.ln-3d-ctl .lap-lbl{min-width:4.5em}
.ln-cube path{stroke:var(--rule);stroke-width:1;fill:none}
.ln-axes path{stroke:var(--ink-3);stroke-width:1.2}
.ln-axes text{font:600 12px var(--mono);fill:var(--ink-2)}
.ln-pl{stroke-width:1.4;fill-opacity:.24;stroke-opacity:.9}
.ln-pl1{fill:var(--accent);stroke:var(--accent)} .ln-pl2{fill:var(--signal);stroke:var(--signal)} .ln-pl3{fill:var(--ok);stroke:var(--ok)}
.ln-ix{stroke:var(--ink);stroke-width:2.2;stroke-linecap:round}
.ln-plab circle{fill-opacity:1;stroke:var(--paper);stroke-width:2}
.ln-plab text{font:700 11px var(--mono);fill:var(--paper);stroke:none}
.ln-sol-pt{fill:var(--ink);stroke:var(--paper);stroke-width:2.5}
.ln-eqs{list-style:none;padding:0;margin:0;display:grid;gap:4px}
.ln-eqs li{display:flex;align-items:center;gap:8px;overflow-x:auto}
.ln-sw{display:inline-grid;place-items:center;width:20px;height:20px;border-radius:50%;font:700 11px var(--mono);color:var(--paper);flex:0 0 auto}
.ln-sw.ln-pl1{background:var(--accent)} .ln-sw.ln-pl2{background:var(--signal)} .ln-sw.ln-pl3{background:var(--ok)}
.lap-pt tr.ln-bad td{background:color-mix(in srgb,#c43c3c 10%,transparent)}
.lap-pt td.ln-badc{color:#c43c3c;font-weight:600}
.ln-two-in{display:grid;grid-template-columns:minmax(0,1fr) minmax(70px,110px);gap:10px}
.ln-luss{display:grid;gap:10px}
@media (min-width:760px){.ln-luss{grid-template-columns:1fr 1fr}}
.ln-luss > div{border:1px dashed var(--rule);border-radius:10px;padding:8px 12px;overflow-x:auto}
.ln-luss .mono{font-size:.76rem;color:var(--ink-3)}
.ln-rho{display:flex;flex-wrap:wrap;gap:6px 16px;font-size:.84rem;color:var(--ink-2)}
.ln-rc{display:inline-flex;align-items:center;gap:6px}
.ln-key{display:inline-block;width:22px;height:0;border-top:3px solid var(--ink-3);vertical-align:middle}
.ln-key-jacobi{border-top:2.5px dashed var(--signal)}
.ln-key-gs{border-top:3px solid var(--accent)}
.ln-key-sor{border-top:3.5px dotted var(--ok)}
.ln-legend{display:flex;flex-wrap:wrap;gap:4px 14px;margin:6px 0 0;font-size:.8rem;color:var(--ink-2)}
.ln-legend span{display:inline-flex;align-items:center;gap:6px}
.lesson .ln-cap,.ln-cap{margin:0 0 6px;font-size:.8rem;color:var(--ink-3)}
.ln-tip{display:flex;flex-wrap:wrap;gap:4px 12px;font:500 .8rem var(--mono);color:var(--ink-2);padding:6px 10px;margin-top:6px;border:1px solid var(--rule);border-radius:8px;background:var(--paper)}
.ln-tip[hidden]{display:none}
.ln-tip span{display:inline-flex;align-items:center;gap:5px}
.ln-it td,.ln-it th{font-family:var(--mono);font-size:.78rem;white-space:nowrap}
.ln-gap{text-align:center!important;color:var(--ink-3)}
.ln-geo:not(:empty){margin-top:12px}
.ln-hbc{display:grid;gap:0 18px}
@media (min-width:700px){.ln-hbc{grid-template-columns:1fr 1fr}}
.ln-hstat{font-size:.78rem;color:var(--ink-2)}
svg.ln-heat-svg{display:block;width:100%;max-width:340px;height:auto;margin:0 auto;border-radius:8px}
svg.ln-heat-svg rect{stroke:none}
.ln-hframe{fill:none!important;stroke:var(--ink)!important;stroke-width:1.4}
.ln-hscale{display:flex;align-items:center;gap:8px;max-width:340px;margin:8px auto 0;font:500 .74rem var(--mono);color:var(--ink-3)}
.ln-hscale i{flex:1;height:10px;border-radius:5px;border:1px solid var(--rule);background:linear-gradient(90deg,var(--paper),var(--accent))}
.ln-dq .ln-qt{overflow-x:auto;line-height:1.9}
.ln-dfb .lap-eq{margin-top:6px}
@media (max-width:560px){
.ln-two-in{grid-template-columns:minmax(0,1fr) 84px}
.ln-res{gap:10px}
.ln-3d-ctl .lap-lbl{min-width:0;flex:0 0 auto}
}
/* page helpers for the three new pages and articles */
.ln-path{display:grid;gap:8px;counter-reset:lnp;padding:0;margin:14px 0;list-style:none}
@media (min-width:760px){.ln-path{grid-template-columns:repeat(4,1fr)}}
.ln-path li{counter-increment:lnp;position:relative;border:1px solid var(--rule);border-radius:12px;background:var(--card);padding:10px 12px 10px 42px;min-width:0}
.ln-path li::before{content:counter(lnp);position:absolute;left:12px;top:11px;width:22px;height:22px;border-radius:50%;background:var(--accent);color:var(--accent-ink);display:grid;place-items:center;font:700 .74rem var(--mono)}
.ln-path a{font-weight:600;text-decoration:none}
.ln-path span{display:block;font-size:.82rem;color:var(--ink-2);margin-top:2px}
.ln-new{display:inline-block;font:700 .66rem var(--mono);letter-spacing:.04em;padding:1px 6px;border-radius:6px;background:var(--accent);color:var(--accent-ink);vertical-align:middle;margin-left:4px}
.ln-code{margin:8px 0;padding:10px 12px;background:var(--paper);border:1px solid var(--rule);border-radius:10px;overflow-x:auto;font:.8rem/1.55 var(--mono);color:var(--ink);white-space:pre}
/* figures from scripts/la_figs.py */
svg.mf.lnf-fig{max-width:560px;margin:0 auto}
.mf-pl1{fill:var(--accent);fill-opacity:.22;stroke:var(--accent);stroke-width:1.1}
.mf-pl2{fill:var(--signal);fill-opacity:.22;stroke:var(--signal);stroke-width:1.1}
.mf-pl3{fill:var(--ok);fill-opacity:.22;stroke:var(--ok);stroke-width:1.1}
.mf-ix{stroke:var(--ink);stroke-width:2;stroke-linecap:round}
.mf-va{stroke:var(--accent);stroke-width:2.4;stroke-linecap:round}
.mf-vb{stroke:var(--signal);stroke-width:2.4;stroke-linecap:round}
.mf-vc{stroke:var(--ok);stroke-width:2.4;stroke-linecap:round}
.mf-boxa{fill:color-mix(in srgb,var(--accent) 10%,var(--card));stroke:var(--accent);stroke-width:1.3}
.mf-boxb{fill:color-mix(in srgb,var(--signal) 10%,var(--card));stroke:var(--signal);stroke-width:1.3}
.mf-boxc{fill:color-mix(in srgb,var(--ok) 10%,var(--card));stroke:var(--ok);stroke-width:1.3}
.mf-sigd{fill:none;stroke:var(--signal);stroke-width:2;stroke-dasharray:6 4}
.mf-node0{fill:var(--accent)} .mf-node1{fill:var(--signal)} .mf-node2{fill:var(--ok)}
.mf-nodet{font:700 11px var(--mono);fill:var(--paper)}
.mf-s{font:11px var(--sans);fill:var(--ink-2)}
/* ==========================================================================
SEQUENCE CALCULATORS (26.11, assets/seq-calc.js) · STRONG INDUCTION (26.12, assets/strong-ind.js)
Phone-first: fields in an auto-fill grid, long math scrolls inside its own box, tables scroll, widgets never widen the page.
========================================================================== */
.sc-lab{gap:10px}
.sc-lab > *,.si-lab > *{min-width:0;max-width:100%}
.sc-form{display:grid;gap:8px 10px;grid-template-columns:repeat(auto-fill,minmax(min(100%,150px),1fr));align-items:end}
.sc-form-sigma{grid-template-columns:minmax(0,1fr) minmax(0,92px) minmax(0,110px)}
@media (max-width:520px){.sc-form-sigma{grid-template-columns:1fr 1fr}.sc-form-sigma .sc-wide{grid-column:1/-1}}
.sc-f{display:flex;flex-direction:column;gap:3px;min-width:0}
.sc-f > span{font:500 .78rem var(--sans);color:var(--ink-2);line-height:1.35}
.sc-f .lap-in{flex:none;width:100%;max-width:none;padding:8px 10px;font-size:.95rem}
.sc-f select.lap-in{font:500 .9rem var(--sans);padding:8px 8px}
.sc-wide{grid-column:1/-1}
@media (min-width:640px){.sc-form > .sc-wide:first-child:not(:only-child){grid-column:span 2}}
.sc-modes,.sc-ex{gap:6px}
@media (max-width:640px){
.sc-modes,.sc-ex,.si-pre{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:thin;padding-bottom:4px}
.sc-modes > .lap-chip,.sc-ex > .lap-chip,.si-pre > .lap-chip{flex:0 0 auto;white-space:nowrap}
.sc-lab .lap-chip{white-space:nowrap}
}
.sc-act{display:flex;flex-wrap:wrap;gap:8px}
.sc-preview{overflow-x:auto;overflow-y:hidden;min-height:2.4em;text-align:center;border:1px dashed var(--rule);border-radius:10px;background:var(--paper);padding:0 8px}
.sc-preview .katex-display{margin:.3em 0}
.sc-out{display:grid;gap:8px;min-width:0}
.sc-out:empty{display:none}
.sc-out .lap-ans{display:grid;gap:2px;min-width:0}
.sc-out .lap-ans p{margin:4px 0}
.sc-method{margin:0;font-size:.88rem;color:var(--ink-2)}
.sc-dec,.sc-terms{margin:0;font:500 .85rem var(--mono);color:var(--ink-2);overflow-x:auto;overflow-y:hidden}
.sc-terms .katex{font-size:1em}
.sc-big{font-size:1.05rem}
.sc-big b{font:600 1.25rem var(--mono);color:var(--ink)}
.sc-warn{margin:0;padding:6px 10px;border-radius:8px;background:color-mix(in srgb,#d4a017 13%,transparent);font-size:.86rem;line-height:1.6}
.sc-grid{display:grid;gap:6px;grid-template-columns:repeat(auto-fill,minmax(min(100%,92px),1fr))}
.sc-cell{border:1px solid var(--rule);border-radius:10px;background:var(--paper);padding:6px 10px;display:flex;flex-direction:column;gap:1px;min-width:0;overflow-x:auto}
.sc-cell > span{font-size:.78rem;color:var(--ink-3)}
.sc-cell > b{font-weight:600;font-size:1.02rem}
.sc-cell small{font:.72rem var(--mono);color:var(--ink-3)}
.sc-steps{border:1px solid var(--rule);border-radius:12px;background:var(--paper);padding:0}
.sc-steps > summary{cursor:pointer;padding:8px 12px;font:600 .9rem var(--sans);color:var(--signal);list-style:none}
.sc-steps > summary::-webkit-details-marker{display:none}
.sc-steps > summary::before{content:"▸ ";color:var(--ink-3)}
.sc-steps[open] > summary::before{content:"▾ "}
.sc-steps > ol{padding:0 12px 10px 2.1em;margin:0}
.sc-steps .lap-steps > li{min-width:0}
.sc-steps .lap-steps p,.sc-steps .lap-steps > li > div{margin:2px 0;line-height:1.75;overflow-x:auto;overflow-y:hidden;max-width:100%}
.sc-steps .table-wrap{margin:6px 0}
.sc-lab .lap-pt td,.sc-lab .lap-pt th{white-space:nowrap}
.sc-lab .lap-pt .mono,.sc-lab .lap-pt td{font-size:.84rem}
.sc-diff th{font:500 .74rem var(--mono);color:var(--ink-3)}
.sc-diff tr.in td{font-weight:600}
.sc-adv{border-left:3px solid #8a5cc2;padding:2px 0 2px 12px}
.sc-adv .lap-bh{margin-top:2px}
.sc-proof > summary{color:var(--accent)}
.sc-prac{border:1.5px dashed var(--accent);border-radius:12px;padding:10px 12px;background:color-mix(in srgb,var(--accent) 5%,var(--card));display:grid;gap:8px}
.sc-prac[hidden]{display:none}
.sc-ph{display:flex;justify-content:space-between;align-items:baseline;gap:8px;flex-wrap:wrap}
.sc-score{font:500 .8rem var(--mono);color:var(--ink-3)}
.sc-pq{line-height:1.8;overflow-x:auto;overflow-y:hidden}
.sc-pa{flex:1 1 160px}
.sc-ok,.sc-no{margin:0;padding:6px 10px;border-radius:8px;font-weight:600}
.sc-ok{background:color-mix(in srgb,var(--ok) 15%,transparent);color:var(--ok)}
.sc-no{background:color-mix(in srgb,#c43c3c 10%,transparent);color:#c43c3c}
.sc-no .katex{color:var(--ink)}
@media (max-width:560px){
.sc-lab{padding:12px 10px}
.sc-out .katex-display > .katex{font-size:1.02em}
.sc-steps > ol{padding:0 8px 8px 1.7em}
.sc-cell > b{font-size:.95rem}
}
/* level ladder on the calculators page */
.sc-levels{display:grid;gap:8px;grid-template-columns:repeat(auto-fit,minmax(min(100%,230px),1fr));margin:12px 0}
.sc-levels a{display:block;text-decoration:none;color:inherit;border:1px solid var(--rule);border-radius:12px;padding:10px 12px;background:var(--card)}
.sc-levels a:hover{border-color:var(--ink-3)}
.sc-levels b{display:block;font-family:var(--serif);margin:2px 0}
.sc-levels small{color:var(--ink-2);font-size:.84rem;line-height:1.5;display:block}
.sc-ml{display:none}
@media (max-width:600px){.sc-1l{display:none}.sc-ml{display:block}}
.sc-note{display:block;font:.72rem var(--sans);color:var(--ink-3);white-space:normal}
.sc-lab .sc-em-t td:first-child,.sc-lab .sc-cmp td:first-child{white-space:normal;min-width:7.5em}
.sc-lab .sc-cmp td{white-space:normal}
.sc-lab .sc-cmp .mono,.sc-lab .sc-em-t .mono{white-space:nowrap}
/* strong induction widgets */
.si-ctl{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:flex-end}
.si-ctl .sc-f{flex:1 1 130px;max-width:240px}
.si-ctl .si-num .lap-in{max-width:150px}
.si-rule{margin:0;font-size:.88rem;color:var(--ink-2);line-height:1.6}
.si-grid{display:grid;gap:5px;grid-template-columns:repeat(auto-fill,minmax(42px,1fr))}
.si-sgrid{grid-template-columns:repeat(auto-fill,minmax(36px,1fr))}
.si-cell{font:500 .82rem var(--mono);border:1px solid var(--rule);border-radius:8px;background:var(--paper);color:var(--ink);padding:6px 0;cursor:pointer;display:flex;flex-direction:column;align-items:center;line-height:1.15;min-width:0;transition:background .15s}
.si-cell small{font-size:.66rem;color:var(--ink-3)}
.si-cell.base{background:color-mix(in srgb,var(--accent) 22%,var(--paper));border-color:var(--accent)}
.si-cell.ok{background:color-mix(in srgb,var(--ok) 20%,var(--paper));border-color:color-mix(in srgb,var(--ok) 55%,var(--rule))}
.si-cell.prime{background:color-mix(in srgb,var(--signal) 18%,var(--paper));border-color:var(--signal)}
.si-cell.fail{background:color-mix(in srgb,#c43c3c 12%,var(--paper));border-color:color-mix(in srgb,#c43c3c 45%,var(--rule));color:var(--ink-2)}
.si-cell.pend{opacity:.35}
.si-cell.frob{outline:2.5px solid #c43c3c;outline-offset:1px}
.si-cell.sel{outline:2.5px solid var(--ink);outline-offset:1px;font-weight:700}
.si-cell.dep{box-shadow:0 0 0 3px color-mix(in srgb,var(--signal) 55%,transparent)}
.si-legend{display:flex;flex-wrap:wrap;align-items:center;gap:4px 10px;font-size:.78rem;color:var(--ink-2)}
.si-key{display:inline-block;width:14px;height:14px;border-radius:4px;border:1px solid var(--rule);vertical-align:-2px;margin-right:2px}
.si-key.base{background:color-mix(in srgb,var(--accent) 22%,var(--paper));border-color:var(--accent)}
.si-key.ok{background:color-mix(in srgb,var(--ok) 20%,var(--paper))}
.si-key.prime{background:color-mix(in srgb,var(--signal) 18%,var(--paper));border-color:var(--signal)}
.si-key.fail{background:color-mix(in srgb,#c43c3c 12%,var(--paper))}
.si-key.frob{outline:2px solid #c43c3c}
.si-msg{line-height:1.7}
.si-tree,.si-tree ul{list-style:none;margin:0;padding-left:18px;position:relative}
.si-tree{padding-left:2px;overflow-x:auto;max-width:100%}
.si-tree li{position:relative;padding:3px 0 3px 14px;white-space:nowrap}
.si-tree ul li::before{content:"";position:absolute;left:0;top:0;bottom:50%;border-left:1.5px solid var(--rule);border-bottom:1.5px solid var(--rule);width:12px;border-radius:0 0 0 6px}
.si-tree ul li:not(:last-child)::after{content:"";position:absolute;left:0;top:50%;bottom:0;border-left:1.5px solid var(--rule)}
.si-node{font:600 .9rem var(--mono);background:var(--paper);border:1px solid var(--rule);border-radius:6px;padding:1px 7px}
.si-leaf{font:700 .9rem var(--mono);color:var(--signal);background:color-mix(in srgb,var(--signal) 12%,var(--paper));border:1px solid var(--signal);border-radius:999px;padding:1px 9px}
.si-tree small{margin-left:6px;color:var(--ink-3);font-size:.76rem}
.si-choc{max-width:420px}
svg.si-choc-svg{display:block;width:100%;height:auto;touch-action:manipulation}
.si-piece rect{fill:#7a4a2a;stroke:#4e2c16;stroke-width:1.5;cursor:pointer;transition:fill .15s}
.si-piece:hover rect{fill:#8c5733}
.si-piece line{stroke:#a87655;stroke-width:1;stroke-dasharray:3 3;pointer-events:none}
:root[data-theme="dark"] .si-piece rect{fill:#9a6440}
.si-count{display:flex;flex-wrap:wrap;gap:6px 14px;font:500 .9rem var(--mono)}
.si-count b{color:var(--accent)}
.si-log{font-family:var(--mono)}
.si-pile{display:flex;flex-wrap:wrap;gap:5px;min-height:24px;padding:6px 0}
.si-coin{width:20px;height:20px;border-radius:50%;background:radial-gradient(circle at 35% 35%,#f6d36b,#c79a1e);border:1px solid #9c7712}
.si-left{margin:0;font:500 .95rem var(--mono)}
.si-ngrid{grid-template-columns:repeat(auto-fill,minmax(38px,1fr))}
.si-fibbar{display:flex;flex-wrap:wrap;gap:4px}
.si-fibbar span{font:500 .76rem var(--mono);padding:2px 7px;border-radius:999px;border:1px solid var(--rule);color:var(--ink-3)}
.si-fibbar span.on{background:var(--signal);border-color:var(--signal);color:#fff;font-weight:700}
.si-zsteps{font-size:.9rem}
.si-tgroups{display:grid;gap:10px}
@media (min-width:700px){.si-tgroups{grid-template-columns:1fr 1fr}}
.si-th{margin:0 0 4px;font:600 .82rem var(--sans);color:var(--ink-2)}
.si-tiles{display:flex;flex-wrap:wrap;gap:6px}
svg.si-til{display:block;height:auto;max-width:100%}
.si-til rect.v{fill:color-mix(in srgb,var(--signal) 30%,var(--card));stroke:var(--signal);stroke-width:1.2}
.si-til rect.h{fill:color-mix(in srgb,var(--accent) 26%,var(--card));stroke:var(--accent);stroke-width:1.2}
svg.si-bplot{max-width:420px}
.si-ord{display:grid;gap:4px}
.si-chosen{margin:0 0 6px;padding-left:1.6em;display:grid;gap:5px}
.si-chosen .si-empty{list-style:none;margin-left:-1.6em;color:var(--ink-3);font-size:.86rem}
.si-pool{display:grid;gap:5px}
.si-ord .fl-line{font-size:.92rem;padding:7px 10px}
.si-ord .fl-line.ok{border-color:var(--ok);background:color-mix(in srgb,var(--ok) 10%,var(--paper))}
.si-lab .fl-line{overflow-x:auto}
@media (max-width:560px){
.si-lab{padding:12px 10px}
.si-grid{grid-template-columns:repeat(auto-fill,minmax(38px,1fr));gap:4px}
.si-sgrid,.si-ngrid{grid-template-columns:repeat(auto-fill,minmax(34px,1fr))}
.si-cell{font-size:.76rem;padding:5px 0}
.si-ctl .sc-f{flex:1 1 120px}
}
.sc-page .steps > li > p,.sc-page .answer,.sc-page .tf-x,.sc-page .sr-q > div > p{overflow-x:auto;overflow-y:hidden}