/* Engimations design system. Mobile first. Tokens first, then layout, then components. */
@font-face{font-family:"Inter";src:url("../fonts/inter-latin-wght-normal.woff2") format("woff2");font-weight:100 900;font-display:swap}
@font-face{font-family:"JetBrains Mono";src:url("../fonts/jetbrains-mono-latin-500-normal.woff2") format("woff2");font-weight:500;font-display:swap}
@font-face{font-family:"JetBrains Mono";src:url("../fonts/jetbrains-mono-latin-700-normal.woff2") format("woff2");font-weight:700;font-display:swap}

:root{
  --bg:#fff;--bg2:#f4f6fa;--bg3:#e9eef5;--ink:#0f1b2d;--ink2:#455468;--ink3:#6b7a8e;--line:#d8e0ea;--card:#fff;
  --navy:#0b2545;--navy2:#13315c;--blue:#1d5fd1;--amber:#f5a524;--accent:#1d5fd1;--accent-ink:#fff;
  --tens:#2563eb;--comp:#e11d48;--load:#d97706;--ok:#15803d;--shadow:0 1px 2px rgba(15,27,45,.06),0 6px 20px rgba(15,27,45,.06);
  --r:12px;--sans:"Inter",system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;--mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --c:#2563eb;--tint:color-mix(in srgb,var(--c) 10%,var(--bg));--tint2:color-mix(in srgb,var(--c) 18%,var(--bg));
  color-scheme:light;
}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--bg:#0d1520;--bg2:#121d2b;--bg3:#1a2839;--ink:#e8eef7;--ink2:#a9b7c9;--ink3:#7f90a6;--line:#27384c;--card:#142031;--blue:#6aa6ff;--accent:#6aa6ff;--accent-ink:#0b1626;--tens:#60a5fa;--comp:#fb7185;--load:#fbbf24;--ok:#4ade80;--shadow:0 1px 2px rgba(0,0,0,.4),0 6px 20px rgba(0,0,0,.3);color-scheme:dark}}
:root[data-theme=dark]{--bg:#0d1520;--bg2:#121d2b;--bg3:#1a2839;--ink:#e8eef7;--ink2:#a9b7c9;--ink3:#7f90a6;--line:#27384c;--card:#142031;--blue:#6aa6ff;--accent:#6aa6ff;--accent-ink:#0b1626;--tens:#60a5fa;--comp:#fb7185;--load:#fbbf24;--ok:#4ade80;--shadow:0 1px 2px rgba(0,0,0,.4),0 6px 20px rgba(0,0,0,.3);color-scheme:dark}
[data-c=mech]{--c:#2563eb}[data-c=som]{--c:#ea580c}[data-c=struct]{--c:#0d9488}[data-c=fluid]{--c:#0284c7}[data-c=thermo]{--c:#dc2626}[data-c=elec]{--c:#7c3aed}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]) [data-c=mech]{--c:#60a5fa}:root:not([data-theme=light]) [data-c=som]{--c:#fb923c}:root:not([data-theme=light]) [data-c=struct]{--c:#2dd4bf}:root:not([data-theme=light]) [data-c=fluid]{--c:#38bdf8}:root:not([data-theme=light]) [data-c=thermo]{--c:#f87171}:root:not([data-theme=light]) [data-c=elec]{--c:#a78bfa}}
:root[data-theme=dark] [data-c=mech]{--c:#60a5fa}:root[data-theme=dark] [data-c=som]{--c:#fb923c}:root[data-theme=dark] [data-c=struct]{--c:#2dd4bf}:root[data-theme=dark] [data-c=fluid]{--c:#38bdf8}:root[data-theme=dark] [data-c=thermo]{--c:#f87171}:root[data-theme=dark] [data-c=elec]{--c:#a78bfa}

*,*::before,*::after{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:84px}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--sans);-webkit-font-smoothing:antialiased;overflow-x:hidden}
.page{min-height:100vh;display:flex;flex-direction:column;background:var(--bg);color:var(--ink)}
main{flex:1;min-width:0}
img,svg{max-width:100%}
a{color:var(--accent);text-underline-offset:3px}
a:hover{text-decoration-thickness:2px}
h1,h2,h3,h4{line-height:1.2;letter-spacing:-.01em;margin:0 0 .5em}
p{margin:0 0 1em}
code{font-family:var(--mono);font-size:.88em;background:var(--bg3);padding:.12em .4em;border-radius:5px}
pre{background:var(--bg3);padding:14px 16px;border-radius:10px;overflow-x:auto;font-size:.85rem;line-height:1.5}
pre code{background:none;padding:0}
.wrap{width:100%;max-width:1200px;margin:0 auto;padding:0 20px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:-999px;top:8px;background:var(--navy);color:#fff;padding:10px 14px;border-radius:8px;z-index:200}
.skip:focus{left:8px}
:focus-visible{outline:3px solid var(--amber);outline-offset:2px;border-radius:4px}
.eyebrow{font-size:.78rem;font-weight:700;letter-spacing:.09em;text-transform:uppercase;color:var(--c);margin:0 0 .5rem}

/* ---------- utility bar + header ---------- */
.util{background:var(--navy);color:#cfe0f5;font-size:.78rem}
.util .wrap{display:flex;align-items:center;gap:16px;min-height:34px;overflow-x:auto;white-space:nowrap;scrollbar-width:none}
.util .wrap::-webkit-scrollbar{display:none}
.util-l{opacity:.7;font-weight:600;letter-spacing:.04em;text-transform:uppercase;font-size:.7rem}
.util nav{display:flex;gap:16px}
.util a{color:#e6f0ff;text-decoration:none;padding:8px 0;display:inline-block}
.util a:hover{text-decoration:underline}
header.top{position:sticky;top:0;z-index:100;background:color-mix(in srgb,var(--bg) 94%,transparent);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--line)}
.bar{display:flex;align-items:center;justify-content:space-between;min-height:62px;position:relative;gap:12px}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:800;font-size:1.2rem;letter-spacing:-.02em}
.wm b{color:var(--blue);font-weight:800}
.burger,.themebtn{background:none;border:1px solid var(--line);color:var(--ink);border-radius:10px;min-width:44px;height:44px;display:inline-grid;place-items:center;cursor:pointer}
.burger:hover,.themebtn:hover{background:var(--bg2)}
nav.menu{display:none;position:absolute;left:0;right:0;top:100%;background:var(--bg);border-bottom:1px solid var(--line);box-shadow:var(--shadow);padding:10px 20px 18px;max-height:calc(100vh - 100px);overflow:auto}
nav.menu.open{display:block}
nav.menu>a,.ddb{display:flex;align-items:center;justify-content:space-between;width:100%;padding:14px 4px;font:600 1rem var(--sans);color:var(--ink);text-decoration:none;background:none;border:0;border-bottom:1px solid var(--line);cursor:pointer;text-align:left;min-height:48px}
nav.menu>a[aria-current=page]{color:var(--accent)}
.dd .mega{display:none}
.dd.open .mega{display:block}
.mcol{border-bottom:1px solid var(--line);padding:2px 0 6px}
.mh{display:flex;align-items:center;justify-content:space-between}
.mh a{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--ink);text-decoration:none;padding:12px 4px;flex:1;min-height:46px}
.mh a svg{color:var(--c)}
.mh a span{overflow:hidden;text-overflow:ellipsis}
.mtog{background:none;border:1px solid var(--line);color:var(--ink);border-radius:8px;width:40px;height:40px;font:600 1.1rem var(--sans);cursor:pointer}
.mcol ul{display:none;list-style:none;margin:0 0 4px;padding:0 0 0 32px}
.mcol.open ul{display:block}
.mcol li a{display:block;padding:9px 4px;color:var(--ink2);text-decoration:none;font-size:.93rem}
.mcol li a:hover{color:var(--accent)}
.mall{display:none;font-size:.85rem;font-weight:600;padding:8px 4px 8px 32px;text-decoration:none}
.mcol.open .mall{display:flex;gap:6px;align-items:center}
.search{position:relative;margin:14px 0 6px}
.search input{width:100%;height:46px;border:1px solid var(--line);border-radius:10px;padding:0 14px;font:inherit;background:var(--bg2);color:var(--ink)}
.results{position:absolute;left:0;right:0;top:50px;margin:0;padding:6px;list-style:none;background:var(--card);border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);max-height:320px;overflow:auto;z-index:20}
.results li a{display:flex;flex-direction:column;padding:10px 12px;border-radius:8px;text-decoration:none;color:var(--ink)}
.results li a:hover,.results li a.act{background:var(--bg2)}
.results small{color:var(--ink3)}
.results .none{padding:12px;color:var(--ink3)}
.themebtn{margin-top:12px}

@media (min-width:961px){
  .burger{display:none}
  nav.menu{display:flex;position:static;border:0;box-shadow:none;padding:0;max-height:none;overflow:visible;align-items:center;gap:2px;background:none;flex:1;justify-content:flex-start;margin-left:18px}
  nav.menu>a,.ddb{width:auto;border:0;padding:0 14px;height:44px;border-radius:10px;font-size:.95rem;gap:6px}
  nav.menu>a:hover,.ddb:hover,.dd.open .ddb{background:var(--bg2)}
  .dd{position:static}
  .dd .mega{position:absolute;left:20px;right:20px;top:100%;margin-top:6px;background:var(--card);border:1px solid var(--line);border-radius:16px;box-shadow:0 20px 50px rgba(11,37,69,.18);padding:22px 24px;grid-template-columns:repeat(3,1fr);gap:8px 28px;max-height:calc(100vh - 140px);overflow:auto}
  .dd.open .mega{display:grid}
  @media (hover:hover){.dd:hover .mega{display:grid}}
  .mcol{border:0;padding:0}
  .mtog{display:none}
  .mh a{padding:6px 0;min-height:0;color:var(--c);font-size:.95rem}
  .mcol ul,.mcol.open ul{display:block;padding:0;margin:4px 0}
  .mcol li a{padding:5px 0;font-size:.9rem}
  .mall,.mcol.open .mall{display:flex;gap:6px;align-items:center;padding:4px 0;color:var(--c)}
  .search{margin:0 0 0 auto;width:260px}
  .search input{height:40px;font-size:.9rem}
  .themebtn{margin:0 0 0 8px}
}

/* ---------- buttons, chips ---------- */
.btn{display:inline-flex;align-items:center;gap:8px;min-height:44px;padding:0 20px;border-radius:10px;border:1.5px solid var(--accent);background:var(--accent);color:var(--accent-ink);font:600 .95rem var(--sans);text-decoration:none;cursor:pointer}
.btn:hover{filter:brightness(1.08);text-decoration:none}
.btn.sm{min-height:40px;padding:0 14px;font-size:.88rem}
.btn.big{min-height:52px;padding:0 26px;font-size:1rem}
.btn.ghost{background:transparent;color:var(--accent)}
.btn.ghost:hover{background:var(--bg2)}
.btn.ghost-d{background:transparent;color:#fff;border-color:rgba(255,255,255,.5)}
.btn.ghost-d:hover{background:rgba(255,255,255,.1)}
.btn.done{background:var(--ok);border-color:var(--ok);color:#fff}
.chip{display:inline-block;padding:5px 12px;border-radius:99px;background:var(--bg3);color:var(--ink);font-size:.82rem;text-decoration:none;font-weight:500}
a.chip:hover{background:var(--tint2)}
.chips{display:flex;flex-wrap:wrap;gap:8px}
.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}

/* ---------- page header (topic / branch / info pages) ---------- */
.phead{background:linear-gradient(180deg,var(--tint) 0,var(--bg) 100%);border-bottom:1px solid var(--line);padding:18px 0 28px}
.crumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:4px 8px;padding:0;margin:0 0 18px;font-size:.84rem;color:var(--ink3)}
.crumbs li+li::before{content:"/";margin-right:8px;color:var(--ink3)}
.crumbs a{color:var(--ink2);text-decoration:none}.crumbs a:hover{text-decoration:underline}
.ptitle{display:flex;gap:16px;align-items:flex-start}
.disc{flex:none;width:48px;height:48px;border-radius:12px;display:inline-grid;place-items:center;background:var(--tint2);color:var(--c)}
.phead h1{font-size:clamp(1.65rem,4.6vw,2.5rem);margin:0}
.phead .eyebrow{margin-bottom:.2rem}
.lede{font-size:1.08rem;color:var(--ink2);max-width:68ch;margin:14px 0 0}
.meta{display:flex;flex-wrap:wrap;gap:8px 18px;margin-top:14px;font-size:.88rem;color:var(--ink2);align-items:center}
.meta>span{display:inline-flex;align-items:center;gap:6px}
.meta .pre{display:inline-flex;flex-wrap:wrap;gap:6px;align-items:center}
.progress{margin-top:16px;max-width:420px}
.progress i{display:block;height:8px;border-radius:99px;background:var(--bg3);overflow:hidden;position:relative}
.progress i::after{content:"";position:absolute;left:0;top:0;bottom:0;width:var(--p,0%);background:var(--c);border-radius:99px}
.progress span{font-size:.82rem;color:var(--ink2);display:block;margin-top:6px}

/* ---------- topic layout ---------- */
.tlayout{display:block;padding-top:24px;padding-bottom:60px}
.tside{margin-bottom:22px}
.sidebox{border:1px solid var(--line);border-radius:var(--r);background:var(--card)}
.sidebox>summary{padding:14px 16px;font-weight:700;cursor:pointer;min-height:48px;display:flex;align-items:center}
.sidebox[open]>summary{border-bottom:1px solid var(--line)}
.su{padding:12px 8px 4px}
.su h3{font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--ink3);margin:0 8px 6px}
.su ul{list-style:none;margin:0;padding:0}
.su a{display:flex;gap:10px;align-items:flex-start;padding:8px 8px;border-radius:8px;color:var(--ink2);text-decoration:none;font-size:.9rem;line-height:1.35}
.su a:hover{background:var(--bg2)}
.su a[aria-current=page]{background:var(--tint2);color:var(--ink);font-weight:600}
.tick{flex:none;width:16px;height:16px;border-radius:50%;border:1.5px solid var(--ink3);margin-top:2px;display:inline-block;position:relative}
.done>.tick,a.done .tick{background:var(--ok);border-color:var(--ok)}
.done>.tick::after,a.done .tick::after{content:"";position:absolute;left:4px;top:1px;width:4px;height:8px;border:solid #fff;border-width:0 2px 2px 0;transform:rotate(45deg)}
.planned{margin:4px 8px 8px;font-size:.78rem;color:var(--ink3)}
.ttoc{display:none}
@media (min-width:900px){
  .tlayout{display:grid;grid-template-columns:260px minmax(0,1fr);gap:36px}
  .tside{position:sticky;top:84px;align-self:start;max-height:calc(100vh - 100px);overflow:auto;margin:0}
  .sidebox>summary{pointer-events:none}.sidebox>summary::-webkit-details-marker{display:none}
}
@media (min-width:1200px){
  .tlayout{grid-template-columns:260px minmax(0,1fr) 200px}
  .ttoc{display:block}
  .stick{position:sticky;top:90px;font-size:.85rem}
  .stick h3{font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--ink3)}
  .stick ul{list-style:none;margin:0;padding:0;border-left:2px solid var(--line)}
  .stick a{display:block;padding:6px 12px;color:var(--ink2);text-decoration:none;line-height:1.35}
  .stick a:hover{color:var(--accent)}
}

/* ---------- article ---------- */
.art{min-width:0;max-width:780px}
.art h2{font-size:1.5rem;margin:2.2rem 0 .7rem;padding-top:.4rem}
.art h3{font-size:1.15rem;margin:1.6rem 0 .5rem}
.art p,.art li{max-width:72ch}
.art ul,.art ol{padding-left:1.3rem;margin:0 0 1.1rem}
.art li{margin-bottom:.35rem}
.art>*:first-child{margin-top:0}
.outcomes{background:var(--tint);border:1px solid var(--tint2);border-radius:var(--r);padding:18px 20px 8px;margin-bottom:8px}
.outcomes h2{font-size:1rem;margin:0 0 .6rem;padding:0;color:var(--ink)}
.outcomes ul{margin-bottom:.6rem}
.eq{margin:1.1rem 0;padding:14px 16px;background:var(--bg2);border-radius:10px;overflow-x:auto;text-align:center;-webkit-overflow-scrolling:touch}
math{font-family:"Cambria Math","STIX Two Math","Latin Modern Math","Noto Sans Math",math,serif;font-size:1.12em}
math[display=block]{display:block math}
.call{border:1px solid var(--line);border-left:5px solid var(--c);border-radius:var(--r);background:var(--card);margin:1.4rem 0;overflow:hidden}
.call-h{font-weight:700;font-size:.82rem;letter-spacing:.06em;text-transform:uppercase;padding:10px 18px;background:var(--tint);color:var(--ink)}
.call-b{padding:14px 18px 4px}
.call.warn{border-left-color:var(--comp)}.call.warn .call-h{background:color-mix(in srgb,var(--comp) 12%,var(--bg))}
.call.key{border-left-color:var(--amber)}.call.key .call-h{background:color-mix(in srgb,var(--amber) 18%,var(--bg))}
.call.example{border-left-color:var(--blue)}.call.example .call-h{background:color-mix(in srgb,var(--blue) 12%,var(--bg))}
.tablewrap{overflow-x:auto;margin:1.2rem 0;-webkit-overflow-scrolling:touch;border:1px solid var(--line);border-radius:10px}
table{border-collapse:collapse;width:100%;font-size:.92rem}
th,td{padding:9px 12px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
th{background:var(--bg2);font-weight:600;white-space:nowrap}
tr:last-child td{border-bottom:0}
.problems{margin-top:2.2rem}
.problems ol{padding-left:0;list-style:none;counter-reset:q}
.problems li{counter-increment:q;border:1px solid var(--line);border-radius:var(--r);padding:16px 18px 14px 56px;position:relative;margin-bottom:12px;background:var(--card)}
.problems li::before{content:counter(q);position:absolute;left:16px;top:14px;width:28px;height:28px;border-radius:50%;background:var(--tint2);color:var(--ink);display:grid;place-items:center;font-weight:700;font-size:.85rem}
.problems .q{margin-bottom:8px}
.problems details summary{cursor:pointer;color:var(--accent);font-weight:600;font-size:.9rem;min-height:36px;display:flex;align-items:center}
.problems .a{margin-top:6px;padding:10px 14px;background:var(--bg2);border-radius:8px;font-size:.95rem}
.formulae{margin-top:2.2rem;border:1px solid var(--line);border-radius:var(--r);padding:6px 18px 10px;background:var(--card)}
.formulae h2{font-size:1.05rem;margin:.8rem 0 .4rem}
dl.fl,.formulae dl{margin:0}
.formulae dl>div,dl.fl>div{display:flex;flex-direction:column;gap:2px;padding:10px 0;border-bottom:1px solid var(--line)}
.formulae dl>div:last-child,dl.fl>div:last-child{border-bottom:0}
dt{font-size:.84rem;color:var(--ink2);font-weight:600}
dd{margin:0;overflow-x:auto}
.lect{margin-top:1.6rem}
.lect details{border:1px dashed var(--ink3);border-radius:var(--r);background:var(--bg2)}
.lect summary{cursor:pointer;padding:14px 18px;font-weight:700;display:flex;gap:10px;align-items:center;min-height:52px}
.lect-b{padding:0 20px 8px;border-top:1px dashed var(--line)}
.pnav{display:grid;grid-template-columns:1fr;gap:12px;margin-top:2.4rem}
.pn{display:flex;flex-direction:column;gap:2px;padding:14px 16px;border:1px solid var(--line);border-radius:var(--r);text-decoration:none;color:var(--ink);background:var(--card)}
.pn:hover{border-color:var(--c)}
.pn small{color:var(--ink3);font-size:.75rem;text-transform:uppercase;letter-spacing:.06em}
.pn span{font-weight:600}
.pn.next{text-align:right}
@media (min-width:640px){.pnav{grid-template-columns:1fr 1fr}}

/* ---------- interactive models ---------- */
.sim{margin:1.6rem 0;border:1px solid var(--line);border-radius:14px;background:var(--card);box-shadow:var(--shadow);overflow:hidden}
.sim figcaption{display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center;padding:10px 16px;background:var(--tint);border-bottom:1px solid var(--line);font-size:.9rem}
.sim .tag{font-size:.7rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase;background:var(--c);color:#fff;padding:3px 8px;border-radius:6px}
:root[data-theme=dark] .sim .tag,:root:not([data-theme=light]) .sim .tag{color:#0b1626}
.sim .cap{color:var(--ink2)}
.sim-ui{padding:14px 16px 8px}
.nojs{color:var(--ink3);font-size:.9rem}
.sim-tools{display:flex;flex-wrap:wrap;gap:8px;padding:0 16px 14px}
.sim-grid{display:grid;grid-template-columns:1fr;gap:14px}
.sim-view{align-self:start;border:1px solid var(--line);border-radius:10px;background:var(--bg);overflow:hidden}
.sim-view svg{display:block;width:100%;height:auto}
.sim-side{display:grid;gap:12px;align-content:start}
.ctl{display:grid;grid-template-columns:1fr auto;gap:2px 10px;align-items:center}
.ctl label{font-size:.84rem;color:var(--ink2);font-weight:600}
.ctl output{font:700 .85rem var(--mono);color:var(--ink)}
.ctl input[type=range]{grid-column:1/-1;width:100%;height:30px;accent-color:var(--c);margin:0;touch-action:pan-y}
.ctl select{grid-column:1/-1;width:100%;height:44px;border-radius:8px;border:1px solid var(--line);background:var(--bg2);color:var(--ink);font:inherit;padding:0 10px}
.seg{display:flex;flex-wrap:wrap;gap:6px}
.seg button{min-height:40px;padding:0 12px;border-radius:8px;border:1px solid var(--line);background:var(--bg2);color:var(--ink);font:600 .85rem var(--sans);cursor:pointer}
.seg button[aria-pressed=true]{background:var(--c);border-color:var(--c);color:#fff}
.ros{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}
.ro{background:var(--bg2);border-radius:8px;padding:8px 10px;min-width:0}
.ro small{display:block;font-size:.72rem;color:var(--ink3);line-height:1.25}
.ro b{font:700 .98rem var(--mono);overflow-wrap:anywhere}
.ro.hi{background:var(--tint2)}
.sim-note{font-size:.82rem;color:var(--ink3);margin:2px 0 0}
@media (min-width:760px){.sim-grid{grid-template-columns:minmax(0,1.5fr) minmax(250px,1fr)}.sim.wide .sim-grid{grid-template-columns:1fr}.sim.wide .ros{grid-template-columns:repeat(4,minmax(0,1fr))}}
svg .ink{stroke:var(--ink);fill:none}
svg .fill-ink{fill:var(--ink)}
svg .mut{stroke:var(--ink3);fill:none}
svg .grid{stroke:var(--line);fill:none}
svg text{font:500 13px var(--sans);fill:var(--ink2)}
svg text.b{font-weight:700;fill:var(--ink)}
svg text.m{font-family:var(--mono);font-size:12px}
svg .acc{stroke:var(--c);fill:none}
svg .acc-f{fill:color-mix(in srgb,var(--c) 22%,transparent);stroke:var(--c)}
svg .ld{stroke:var(--load);fill:var(--load)}
svg .ld-l{stroke:var(--load);fill:none}
svg .tn{stroke:var(--tens);fill:none}
svg .cp{stroke:var(--comp);fill:none}
svg .body{fill:color-mix(in srgb,var(--ink3) 25%,var(--bg));stroke:var(--ink2)}
svg .mem{fill:none;stroke-linecap:round}
svg .hit{cursor:pointer}

/* ---------- branch page ---------- */
.blayout{display:grid;grid-template-columns:1fr;gap:28px;padding-top:28px;padding-bottom:64px}
.unit{margin-bottom:26px}
.unit h2{font-size:1.2rem;display:flex;flex-direction:column;gap:2px;margin-bottom:10px}
.unit h2 span{font-size:.72rem;font-weight:800;letter-spacing:.09em;text-transform:uppercase;color:var(--c)}
.unit ol{list-style:none;margin:0;padding:0;border:1px solid var(--line);border-radius:var(--r);overflow:hidden;background:var(--card)}
.unit li+li{border-top:1px solid var(--line)}
.unit li a,.unit li .row{display:grid;grid-template-columns:32px 1fr auto;gap:12px;align-items:center;padding:14px 16px;color:var(--ink);text-decoration:none}
.unit li a:hover{background:var(--tint)}
.unit .num{width:28px;height:28px;border-radius:50%;background:var(--tint2);display:grid;place-items:center;font-size:.8rem;font-weight:700}
.unit .tt b{display:block;font-size:.98rem}
.unit .tt small{display:block;color:var(--ink2);font-size:.84rem;margin-top:2px;line-height:1.4}
.unit .st{font-size:.8rem;color:var(--ink2);display:flex;gap:8px;align-items:center;white-space:nowrap}
.unit .st em{font-style:normal;background:var(--bg3);padding:2px 9px;border-radius:99px}
.unit .st .tick{margin:0}
.unit li.planned{opacity:.7}
.unit li.planned .num{background:var(--bg3)}
.unit li a.done .tick{background:var(--ok)}
.bside .card{border:1px solid var(--line);border-radius:var(--r);padding:18px;margin-bottom:16px;background:var(--card)}
.bside h2{font-size:.95rem;margin-bottom:.6rem}
.bside ul{margin:0;padding-left:1.1rem}.bside li{margin-bottom:.4rem;font-size:.92rem}
.bside ul.plain{list-style:none;padding:0}.bside ul.plain a{display:flex;gap:8px;align-items:center;text-decoration:none;color:var(--ink);padding:5px 0}
@media (min-width:960px){.blayout{grid-template-columns:minmax(0,1fr) 320px;gap:40px}.unit h2{flex-direction:row;align-items:baseline;gap:12px}}
@media (max-width:520px){.unit li a,.unit li .row{grid-template-columns:28px 1fr;}.unit .st{grid-column:2}}

/* ---------- homepage ---------- */
.hero{background:radial-gradient(1200px 500px at 85% 0,rgba(56,189,248,.18),transparent 60%),linear-gradient(160deg,var(--navy) 0,var(--navy2) 100%);color:#fff;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.05) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.05) 1px,transparent 1px);background-size:32px 32px;mask-image:linear-gradient(180deg,#000,transparent 90%)}
.heroin{position:relative;display:grid;gap:34px;padding-top:48px;padding-bottom:56px;align-items:center}
.hero .eyebrow{color:var(--amber)}
.hero h1{font-size:clamp(2.1rem,6.4vw,3.6rem);font-weight:800;letter-spacing:-.03em;margin-bottom:.4em}
.hero h1 em{font-style:normal;color:#7dd3fc}
.hero .lede{color:#d4e2f4;font-size:clamp(1rem,2.4vw,1.15rem)}
.hero .btn{background:var(--amber);border-color:var(--amber);color:#1a1200}
.hero .btn.ghost-d{background:transparent;border-color:rgba(255,255,255,.5);color:#fff}
.stats{display:grid;grid-template-columns:repeat(2,1fr);gap:14px 18px;margin:30px 0 0;padding-top:22px;border-top:1px solid rgba(255,255,255,.18)}
.stats dt{font:800 1.9rem var(--sans);color:#fff;line-height:1}
.stats dd{margin:4px 0 0;font-size:.82rem;color:#b8cbe3}
.heroviz{color:#fff}
.heroart{width:100%;height:auto;display:block;border:1px solid rgba(255,255,255,.14);border-radius:16px;background:rgba(7,22,44,.45)}
@media (min-width:900px){.heroin{grid-template-columns:1.05fr .95fr;padding-top:72px;padding-bottom:80px}.stats{grid-template-columns:repeat(4,auto);justify-content:start;gap:30px}}
.sec{padding:56px 0}
.sec.alt{background:var(--bg2);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.sh{max-width:720px;margin-bottom:28px}
.sh h2,.cinfo h2{font-size:clamp(1.55rem,4vw,2.2rem);margin-bottom:.4em}
.sh p{color:var(--ink2);font-size:1.05rem}
.bgrid{display:grid;gap:18px;grid-template-columns:1fr}
@media (min-width:640px){.bgrid{grid-template-columns:repeat(2,1fr)}}
@media (min-width:1000px){.bgrid{grid-template-columns:repeat(3,1fr)}}
.bcard{border:1px solid var(--line);border-top:4px solid var(--c);border-radius:var(--r);background:var(--card);padding:20px;display:flex;flex-direction:column;box-shadow:var(--shadow)}
.bc-h{display:flex;align-items:center;gap:12px;margin-bottom:10px}
.bc-h h3{margin:0;font-size:1.15rem}.bc-h a{color:var(--ink);text-decoration:none}
.bcard>p{color:var(--ink2);font-size:.94rem;margin-bottom:12px}
.bcard ul{margin:0 0 16px;padding:0;list-style:none;border-top:1px solid var(--line)}
.bcard li a{display:block;padding:8px 0;border-bottom:1px solid var(--line);color:var(--ink);text-decoration:none;font-size:.92rem}
.bcard li a:hover{color:var(--c)}
.bc-f{margin-top:auto;display:flex;justify-content:space-between;align-items:center;gap:10px;font-size:.82rem;color:var(--ink2)}
.bc-f a{display:inline-flex;gap:6px;align-items:center;font-weight:700;color:var(--c);text-decoration:none;min-height:40px}
.cgrid,.trygrid,.lgrid{display:grid;gap:32px;grid-template-columns:1fr;align-items:start}
@media (min-width:900px){.cgrid{grid-template-columns:5fr 7fr}.trygrid{grid-template-columns:4fr 7fr}.lgrid{grid-template-columns:5fr 7fr}}
.cinfo p{color:var(--ink2);font-size:1.03rem}
.ticks{list-style:none;padding:0;margin:0 0 22px}
.ticks li{position:relative;padding-left:28px;margin-bottom:8px}
.ticks li::before{content:"";position:absolute;left:3px;top:6px;width:6px;height:11px;border:solid var(--ok);border-width:0 2.5px 2.5px 0;transform:rotate(45deg)}
.mods{display:grid;gap:14px;grid-template-columns:1fr}
@media (min-width:640px){.mods{grid-template-columns:1fr 1fr}}
.mod{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px 18px}
.mod h3{font-size:1rem;display:flex;flex-direction:column;gap:2px;margin-bottom:8px}
.mod h3 span{font-size:.7rem;letter-spacing:.09em;text-transform:uppercase;color:#ea580c;font-weight:800}
.mod ul{list-style:none;margin:0;padding:0}
.mod li{display:flex;justify-content:space-between;gap:10px;padding:7px 0;border-top:1px solid var(--line);font-size:.9rem}
.mod li span:last-child{color:var(--ink3);font-size:.78rem;white-space:nowrap}
.mod .pl{color:var(--ink3)}
.mod a{color:var(--ink);text-decoration:none}.mod a:hover{color:var(--accent)}
.steps{display:grid;gap:16px;grid-template-columns:1fr}
@media (min-width:640px){.steps{grid-template-columns:1fr 1fr}}
@media (min-width:1000px){.steps{grid-template-columns:repeat(4,1fr)}}
.step{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px}
.step .n{width:34px;height:34px;border-radius:50%;background:var(--navy);color:#fff;display:grid;place-items:center;font-weight:800;margin-bottom:12px}
.step h3{font-size:1.05rem}.step p{color:var(--ink2);font-size:.94rem;margin:0}
.lfeat{list-style:none;margin:0;padding:0;display:grid;gap:12px;grid-template-columns:1fr}
@media (min-width:640px){.lfeat{grid-template-columns:1fr 1fr}}
.lfeat li{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px 18px}
.lfeat b{display:block;margin-bottom:2px}.lfeat span{color:var(--ink2);font-size:.9rem}
.fgrid2{display:grid;gap:14px;grid-template-columns:1fr}
@media (min-width:640px){.fgrid2{grid-template-columns:1fr 1fr}}
@media (min-width:1000px){.fgrid2{grid-template-columns:repeat(3,1fr)}}
.fcard{display:flex;flex-direction:column;gap:6px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px 18px;text-decoration:none;color:var(--ink);overflow:hidden}
.fcard:hover{border-color:var(--accent)}
.fcard .fl{font-size:.8rem;font-weight:700;color:var(--ink2)}
.fcard .eq{background:none;padding:6px 0;margin:0;text-align:left}
.fcard small{color:var(--ink3);font-size:.78rem}
.pgrid{display:grid;gap:14px;grid-template-columns:1fr}
@media (min-width:640px){.pgrid{grid-template-columns:1fr 1fr}}
@media (min-width:1000px){.pgrid{grid-template-columns:repeat(3,1fr)}}
.pcard{display:grid;grid-template-columns:auto 1fr;gap:4px 14px;align-items:start;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px;text-decoration:none;color:var(--ink)}
.pcard:hover{border-color:var(--c);box-shadow:var(--shadow)}
.pcard .disc{grid-row:span 3;width:40px;height:40px}
.pcard small{color:var(--ink2);font-size:.85rem;line-height:1.4}
.pcard .meta{margin:4px 0 0;font-size:.78rem;color:var(--ink3)}
.sec.note{padding:36px 0}
.scope{max-width:820px}.scope h2{font-size:1.1rem}.scope p{color:var(--ink2);font-size:.95rem}
.home .sim{margin:0}

/* ---------- info pages ---------- */
.pbody{padding:34px 0 64px}
.prose{max-width:780px}
.prose h2{font-size:1.35rem;margin-top:2rem}
.prose li{margin-bottom:.4rem}
.callbox{background:var(--tint);border:1px solid var(--tint2);border-left:5px solid var(--c);border-radius:var(--r);padding:16px 20px;margin-bottom:18px}
.fsec{margin:34px 0}
.fsec h2{display:flex;gap:10px;align-items:center;color:var(--c);font-size:1.3rem}
.ftopic{border:1px solid var(--line);border-radius:var(--r);padding:6px 18px 10px;margin-bottom:14px;background:var(--card);break-inside:avoid}
.ftopic h3{font-size:1rem;margin:.8rem 0 .2rem}.ftopic h3 a{color:var(--ink);text-decoration:none}

/* ---------- footer ---------- */
.foot{background:var(--navy);color:#cfe0f5;margin-top:auto;padding:44px 0 26px;font-size:.92rem}
.foot a{color:#e6f0ff;text-decoration:none}.foot a:hover{text-decoration:underline}
.foot .brand{color:#fff}.foot .wm b{color:#7dd3fc}
.fgrid{display:grid;gap:28px;grid-template-columns:1fr}
@media (min-width:760px){.fgrid{grid-template-columns:1.4fr 1fr 1fr}}
.foot h2{font-size:.75rem;letter-spacing:.09em;text-transform:uppercase;color:#8fb0d9;margin-bottom:.7rem}
.foot .h2b{margin-top:1.4rem}
.foot ul{list-style:none;margin:0;padding:0}.foot li a{display:inline-block;padding:5px 0}
.fnote{margin-top:12px;max-width:34ch;color:#b8cbe3}
.fpriv{margin-top:30px;padding-top:20px;border-top:1px solid rgba(255,255,255,.14);font-size:.84rem;color:#b8cbe3;max-width:90ch}
.fcopy{font-size:.78rem;color:#8fb0d9;margin:10px 0 0}

/* ---------- embed ---------- */
body.embed .page{background:var(--bg)}
.embedbar{display:flex;justify-content:space-between;gap:12px;padding:10px 14px;background:var(--navy);color:#cfe0f5;font-size:.8rem}
.embedbar a{color:#fff;font-weight:600;text-decoration:none}
.embedwrap{padding:10px}
.embedwrap .sim{margin:0;box-shadow:none}

/* ---------- print ---------- */
@media print{
  .util,header.top,.foot,.tside,.ttoc,.pnav,.sim-tools,.actions,.sim-ui .seg,.skip,.btn,.sim-side .ctl{display:none!important}
  body{background:#fff;color:#000;font-size:11pt}
  .tlayout{display:block;padding:0}.art{max-width:none}
  .phead{background:none;border-bottom:1px solid #999;padding:0 0 10px}
  .sim,.call,.problems li,.formulae,.ftopic{break-inside:avoid;box-shadow:none}
  .lect details{border:1px solid #999}
  a{color:#000;text-decoration:none}
  .wrap{max-width:none;padding:0}
}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important;animation:none!important}}