:root{
  --bg:#f5f7fb;--surface:#fff;--surface2:#eef2f9;--text:#141a2b;--muted:#5b6479;--line:#dde3ef;
  --accent:#2457d6;--accent2:#0e8f9c;--ok:#16a34a;--bad:#dc2626;--shadow:0 8px 30px rgba(20,30,60,.08);
  --mc:var(--accent);--r:16px;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){--bg:#0a0e1b;--surface:#121829;--surface2:#1a2238;--text:#e8ecf7;--muted:#98a3bd;--line:#252e48;--accent:#4f83ff;--accent2:#22b8c6;--shadow:0 8px 30px rgba(0,0,0,.35);color-scheme:dark}
}
:root[data-theme="dark"]{--bg:#0a0e1b;--surface:#121829;--surface2:#1a2238;--text:#e8ecf7;--muted:#98a3bd;--line:#252e48;--accent:#4f83ff;--accent2:#22b8c6;--shadow:0 8px 30px rgba(0,0,0,.35);color-scheme:dark}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;-webkit-font-smoothing:antialiased}
a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}
h1,h2,h3,h4{line-height:1.2;margin:0 0 .5em}
button{font:inherit;cursor:pointer}
.top{position:sticky;top:env(safe-area-inset-top,0px);z-index:20;display:flex;gap:20px;align-items:center;padding-block:12px;padding-left:max(24px,env(safe-area-inset-left,0px));padding-right:max(24px,env(safe-area-inset-right,0px));background:color-mix(in srgb,var(--bg) 80%,transparent);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.brand{font-weight:800;font-size:1.15rem;color:var(--text);display:flex;align-items:center;gap:8px}
.brand:hover{text-decoration:none}
.logo{background:linear-gradient(135deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;color:transparent;font-size:1.4rem}
.top nav{display:flex;gap:4px}
.top nav a{color:var(--muted);padding:6px 12px;border-radius:999px;font-weight:600;font-size:.95rem}
.top nav a:hover,.top nav a.on{background:var(--surface2);color:var(--text);text-decoration:none}
.search{margin-left:auto}
.search input{width:260px;max-width:40vw;padding:9px 14px;border-radius:999px;border:1px solid var(--line);background:var(--surface);color:var(--text)}
main{max-width:1200px;margin:0 auto;padding-block:24px 60px;padding-left:max(24px,env(safe-area-inset-left,0px));padding-right:max(24px,env(safe-area-inset-right,0px));min-height:70vh}
.foot{max-width:1200px;margin:0 auto;padding-block:24px;padding-left:max(24px,env(safe-area-inset-left,0px));padding-right:max(24px,env(safe-area-inset-right,0px));color:var(--muted);font-size:.85rem;border-top:1px solid var(--line)}
.foot p{margin:.3em 0}
.foot a{color:var(--muted);text-decoration:underline}
.promo{display:flex;gap:12px;align-items:center;justify-content:center;flex-wrap:wrap;padding-block:8px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px));background:var(--surface2);border-bottom:1px solid var(--line);font-size:.9rem}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:20px;box-shadow:var(--shadow)}
.btn{display:inline-flex;align-items:center;gap:8px;padding:10px 18px;border-radius:999px;border:1px solid var(--line);background:var(--surface);color:var(--text);font-weight:600}
.btn:hover{text-decoration:none;border-color:var(--accent)}
.btn.primary{background:linear-gradient(135deg,var(--accent),var(--accent2));color:#fff;border:0}
.chip{display:inline-block;padding:3px 10px;border-radius:999px;background:var(--surface2);color:var(--muted);font-size:.8rem;font-weight:600;border:1px solid var(--line);margin:2px 4px 2px 0}
.chip.on{background:var(--accent);color:#fff;border-color:transparent}
/* hero */
.hero{display:grid;grid-template-columns:1.1fr .9fr;gap:24px;align-items:center;margin-bottom:32px}
.hero h1{font-size:clamp(2rem,4.5vw,3.4rem);letter-spacing:-.02em}
.grad{background:linear-gradient(135deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{font-size:1.1rem;color:var(--muted);max-width:52ch}
.hero .cta{display:flex;gap:12px;flex-wrap:wrap;margin:20px 0}
.stats{display:flex;gap:24px;flex-wrap:wrap;margin-top:8px}
.stats b{display:block;font-size:1.6rem}
.stats span{color:var(--muted);font-size:.85rem}
.stage{position:relative;border-radius:24px;overflow:hidden;background:radial-gradient(circle at 50% 30%,color-mix(in srgb,var(--accent) 22%,var(--surface)),var(--surface));border:1px solid var(--line);min-height:420px}
.stage canvas{display:block;width:100%;height:100%;touch-action:none}
.stage.big{min-height:560px;height:70vh}
.tip{position:absolute;pointer-events:none;background:var(--text);color:var(--bg);padding:4px 10px;border-radius:8px;font-size:.8rem;transform:translate(12px,-28px);white-space:nowrap}
/* grid */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.mod{display:block;color:inherit;position:relative;overflow:hidden;transition:transform .15s,border-color .15s}
.mod:hover{transform:translateY(-3px);border-color:var(--mc);text-decoration:none}
.mod::before{content:"";position:absolute;inset:0 0 auto 0;height:4px;background:var(--mc)}
.mod .em{font-size:2rem}
.mod h3{margin:.3em 0 .2em}
.mod p{color:var(--muted);font-size:.9rem;margin:0 0 12px}
.meta{display:flex;gap:10px;flex-wrap:wrap;color:var(--muted);font-size:.8rem}
.bar{height:6px;border-radius:99px;background:var(--surface2);overflow:hidden;margin-top:10px}
.bar i{display:block;height:100%;background:var(--mc);border-radius:99px}
.soon{opacity:.55}
h3.cat{margin:28px 0 12px;font-size:.85rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
/* module layout */
.modhead{display:flex;gap:16px;align-items:center;margin-bottom:16px;border-left:6px solid var(--mc);padding-left:16px}
.modhead .em{font-size:2.4rem}
.tabs{display:flex;gap:6px;margin:12px 0 20px;flex-wrap:wrap}
.tabs a{padding:8px 16px;border-radius:999px;font-weight:600;color:var(--muted);background:var(--surface);border:1px solid var(--line)}
.tabs a.on{background:var(--mc);color:#fff;border-color:transparent}
.tabs a:hover{text-decoration:none}
.split{display:grid;grid-template-columns:280px 1fr;gap:24px;align-items:start}
.toc{position:sticky;top:76px;max-height:calc(100vh - 100px);overflow:auto;padding:12px}
.toc a{display:flex;gap:8px;align-items:flex-start;color:var(--text);padding:8px 10px;border-radius:10px;font-size:.92rem}
.toc a:hover{background:var(--surface2);text-decoration:none}
.toc a.on{background:color-mix(in srgb,var(--mc) 16%,transparent);font-weight:700}
.toc .lv{font-size:.7rem;color:var(--muted);border:1px solid var(--line);border-radius:6px;padding:0 5px;margin-left:auto}
.article h2{font-size:1.9rem}
.article h4{margin-top:1.2em;color:var(--mc)}
.article p,.article li{max-width:75ch}
.article table{display:block;overflow-x:auto;border-collapse:collapse;margin:1em 0}
.article th,.article td{border:1px solid var(--line);padding:8px 12px;text-align:left}
.article th{background:var(--surface2)}
.article blockquote{margin:1em 0;padding:8px 16px;border-left:4px solid var(--mc);background:var(--surface2);border-radius:0 10px 10px 0}
.article code{background:var(--surface2);padding:1px 6px;border-radius:6px}
.box{border-radius:12px;padding:14px 18px;margin:18px 0;border:1px solid var(--line);background:var(--surface2)}
.box h4{margin:0 0 6px}
.box.key{border-left:5px solid var(--ok)}
.box.warn{border-left:5px solid #f59e0b}
.formula{border-left:5px solid var(--mc);background:var(--surface2);border-radius:12px;padding:12px 16px;margin:12px 0}
.formula .expr{font:600 1.15rem ui-monospace,Consolas,monospace}
.formula ul{margin:.4em 0;padding-left:1.2em;color:var(--muted);font-size:.9rem}
.pager{display:flex;justify-content:space-between;gap:12px;margin-top:28px}
.done{margin-top:16px}
/* calculators */
.calc h3{margin-bottom:4px}
.calc .desc{color:var(--muted);font-size:.9rem;margin:0 0 12px}
.fields{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px}
.fields label{display:flex;flex-direction:column;gap:3px;font-size:.8rem;color:var(--muted);font-weight:600}
.fields input,.sel{padding:8px 10px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--text);font:inherit}
.out{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px;margin-top:14px}
.res{background:color-mix(in srgb,var(--mc) 12%,var(--surface));border-radius:12px;padding:10px 14px}
.res span{display:block;font-size:.78rem;color:var(--muted)}
.res b{font-size:1.25rem}.res small{color:var(--muted);font-weight:600}
.calc .note{font-size:.8rem;color:var(--muted);margin:10px 0 0}
.calcs{display:grid;grid-template-columns:repeat(auto-fill,minmax(380px,1fr));gap:16px}
/* quiz */
.quiz{max-width:760px}
.quiz .q{font-size:1.2rem;font-weight:700;margin:12px 0}
.opt{display:block;width:100%;text-align:left;padding:12px 16px;margin:8px 0;border-radius:12px;border:1px solid var(--line);background:var(--surface);color:var(--text)}
.opt:hover:not(:disabled){border-color:var(--accent)}
.opt.good{background:color-mix(in srgb,var(--ok) 18%,var(--surface));border-color:var(--ok)}
.opt.bad{background:color-mix(in srgb,var(--bad) 16%,var(--surface));border-color:var(--bad)}
.expl{margin-top:10px;padding:12px 16px;border-radius:12px;background:var(--surface2)}
.progress{display:flex;justify-content:space-between;color:var(--muted);font-size:.85rem}
/* flashcards */
.fc{perspective:1000px;max-width:620px;margin:0 auto}
.fcard{position:relative;min-height:260px;transform-style:preserve-3d;transition:transform .5s;cursor:pointer}
.fcard.flip{transform:rotateY(180deg)}
.fcard>div{position:absolute;inset:0;backface-visibility:hidden;display:grid;place-items:center;text-align:center;padding:28px;border-radius:20px;border:1px solid var(--line);background:var(--surface);box-shadow:var(--shadow);font-size:1.15rem}
.fcard .back{transform:rotateY(180deg);background:color-mix(in srgb,var(--mc) 14%,var(--surface))}
.fcctl{display:flex;gap:10px;justify-content:center;margin-top:18px;flex-wrap:wrap}
/* anatomy */
.anat{display:grid;grid-template-columns:1.4fr 1fr;gap:20px;align-items:start}
.panel{display:flex;flex-direction:column;gap:14px}
.seg{display:inline-flex;border:1px solid var(--line);border-radius:999px;overflow:hidden}
.seg button{padding:7px 16px;border:0;background:var(--surface);color:var(--muted);font-weight:600}
.seg button.on{background:var(--accent);color:#fff}
.lab input[type=range]{width:100%}
.lab{display:grid;gap:8px}
.empty{color:var(--muted);text-align:center;padding:40px 0}
@media (max-width:900px){
  .hero,.anat,.split{grid-template-columns:1fr}
  .toc{position:static;max-height:none}
  .top{flex-wrap:wrap;gap:8px 14px;padding-block:10px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
  .search{margin-left:0;flex:1 1 100%;order:3}.search input{width:100%;max-width:none}
  main{padding-block:16px 48px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
  .foot{padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
  .calcs{grid-template-columns:1fr}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

.article h1{font-size:1.9rem}.crumbs{color:var(--muted);font-size:.9rem;margin:0 0 12px}.crumbs a{color:var(--muted)}
.lst{columns:2 300px;list-style:none;padding:0;margin:0}.lst li{margin:4px 0;break-inside:avoid}