:root{
  --bg:#090b10;
  --bg2:#0d1017;
  --panel:#111620;
  --panel2:#151b26;
  --text:#f7f8fb;
  --muted:#9ca7b7;
  --line:#252d3b;
  --line2:#303a4a;
  --accent:#86f1c1;
  --accent2:#8aa8ff;
  --warm:#ffd98a;
  --max:1180px;
  --header:68px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;background:var(--bg);scroll-snap-type:y proximity}
body{margin:0;background:
  radial-gradient(circle at 18% 8%,rgba(138,168,255,.10),transparent 28rem),
  radial-gradient(circle at 88% 20%,rgba(134,241,193,.07),transparent 25rem),
  var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.55}
a{color:inherit}button,input{font:inherit}
.top-progress{position:fixed;left:0;right:0;top:0;height:2px;background:rgba(255,255,255,.04);z-index:60}.top-progress span{display:block;width:0;height:100%;background:linear-gradient(90deg,var(--accent2),var(--accent));transition:width .25s ease}
.site-header{position:fixed;z-index:50;left:0;right:0;top:2px;height:var(--header);display:flex;align-items:center;justify-content:space-between;padding:0 max(22px,calc((100vw - var(--max))/2));background:linear-gradient(180deg,rgba(9,11,16,.92),rgba(9,11,16,.58),transparent);backdrop-filter:blur(14px);pointer-events:none}
.brand,.header-actions{pointer-events:auto}.brand{display:flex;align-items:center;gap:7px;text-decoration:none;font-weight:800;letter-spacing:-.03em}.brand-mark{display:grid;place-items:center;width:31px;height:31px;border-radius:9px;background:linear-gradient(135deg,var(--accent2),var(--accent));color:#07100d;font-size:13px;letter-spacing:-.03em}.brand>span:last-child{font-size:15px;color:#dfe5ef}.header-actions{display:flex;align-items:center;gap:10px}.progress,.ghost-btn{border:1px solid rgba(255,255,255,.08);background:rgba(17,22,32,.74);color:#98a4b4;border-radius:999px;font-size:11px;letter-spacing:.04em;padding:7px 10px;backdrop-filter:blur(10px)}.ghost-btn{cursor:pointer}.ghost-btn:hover{color:#fff;border-color:var(--line2)}.ghost-btn span{margin-left:4px}
.loading{min-height:100svh;display:grid;place-content:center;text-align:center}.loading div{font-size:clamp(72px,18vw,180px);font-weight:900;letter-spacing:-.08em}.loading small{color:var(--muted)}
.lesson{min-height:100svh;display:flex;align-items:center;padding:calc(var(--header) + 42px) 24px 64px;scroll-margin-top:0;scroll-snap-align:start}.lesson-shell{width:min(100%,var(--max));margin:auto}.phase-line{display:flex;align-items:center;gap:12px;margin-bottom:18px}.phase-badge{display:inline-flex;align-items:center;gap:7px;border:1px solid rgba(138,168,255,.22);background:rgba(138,168,255,.06);color:#b9c8ff;border-radius:999px;padding:6px 9px;font-size:10px;text-transform:uppercase;letter-spacing:.12em;font-weight:800}.phase-dot{width:6px;height:6px;border-radius:50%;background:var(--accent2);box-shadow:0 0 16px rgba(138,168,255,.8)}.phase-subtitle{font-size:11px;color:#6f7b8c;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.lesson-grid{display:grid;grid-template-columns:minmax(0,1.08fr) minmax(340px,.92fr);gap:46px;align-items:start}.copy{min-width:0}.lesson h1{font-size:clamp(50px,7vw,88px);line-height:.94;letter-spacing:-.058em;margin:0 0 12px;text-wrap:balance}.lesson:first-child h1{font-size:clamp(76px,13vw,150px)}.alias{font-size:14px;color:#758194;margin:0 0 18px}.definition{font-size:clamp(20px,2.25vw,28px);line-height:1.38;color:#e5eaf2;margin:0 0 28px;max-width:760px;text-wrap:pretty}.micro-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:20px}.micro-card{min-height:120px;border:1px solid var(--line);border-radius:17px;background:linear-gradient(180deg,rgba(21,27,38,.82),rgba(15,19,27,.82));padding:16px 17px}.micro-card.sre{grid-column:1/-1;min-height:auto;border-color:rgba(134,241,193,.24);background:linear-gradient(180deg,rgba(134,241,193,.07),rgba(17,22,32,.66))}.micro-card small,.visual-label,.remember small{display:block;color:#78869a;text-transform:uppercase;letter-spacing:.13em;font-size:9px;font-weight:850;margin-bottom:7px}.micro-card.sre small,.remember small{color:var(--accent)}.micro-card p{margin:0;color:#cbd3df;font-size:14px;line-height:1.6}.micro-card.sre p{color:#dcebe4}
.visual{position:sticky;top:calc(var(--header) + 34px);display:grid;gap:12px}.visual-card{position:relative;overflow:hidden;border:1px solid var(--line);border-radius:22px;background:linear-gradient(145deg,rgba(22,28,39,.94),rgba(13,17,24,.92));padding:19px;box-shadow:0 28px 70px rgba(0,0,0,.18)}.visual-card:before{content:"";position:absolute;inset:0;background:radial-gradient(circle at 100% 0,rgba(138,168,255,.11),transparent 38%);pointer-events:none}.concept-map{position:relative;display:grid;gap:11px;padding:4px 0 16px}.concept-node{position:relative;border:1px solid var(--line);border-radius:14px;padding:12px 14px;background:#0d1118;color:#7f8b9b;font-size:12px}.concept-node.current{border-color:rgba(134,241,193,.45);background:linear-gradient(135deg,rgba(134,241,193,.12),rgba(138,168,255,.08));color:#f4fff9;font-size:14px;font-weight:800}.concept-node.current:before{content:"YOU ARE HERE";display:block;color:var(--accent);font-size:8px;letter-spacing:.13em;margin-bottom:4px}.concept-arrow{height:12px;display:grid;place-items:center;color:#526073;font-size:17px;line-height:1}.picture{position:relative;margin-top:2px;border:1px solid rgba(255,255,255,.07);border-radius:17px;background-color:#0b0f16;background-image:linear-gradient(rgba(255,255,255,.025) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.025) 1px,transparent 1px);background-size:22px 22px;padding:18px;overflow:auto}.picture pre{margin:0;min-width:max-content;color:#d7e0ec;font:600 13px/1.55 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;white-space:pre;text-align:left}.analogy{border-top:1px solid var(--line);margin-top:16px;padding-top:15px}.analogy p{margin:0;color:#aeb9c8;font-size:13px;line-height:1.55}.analogy strong{color:#fff}
.remember{margin:22px 0 0;border:1px solid rgba(255,217,138,.18);background:rgba(255,217,138,.045);border-radius:16px;padding:15px 17px}.remember small{color:var(--warm)}.remember strong{font-size:15px;line-height:1.48;color:#f4ead2}.detail{margin:14px 0 0;border:1px solid var(--line);border-radius:14px;background:rgba(255,255,255,.015);padding:0 14px}.detail summary{cursor:pointer;color:#96a2b2;font-size:12px;padding:11px 0}.detail p{color:#9faaba;font-size:13px;margin:0 0 13px}
.next-wrap{margin-top:34px;border-top:1px solid var(--line);padding-top:20px}.next{display:flex;align-items:center;justify-content:space-between;gap:24px;text-decoration:none;border:1px solid var(--line);border-radius:18px;background:linear-gradient(135deg,#111722,#0d1118);padding:17px 18px;transition:transform .18s ease,border-color .18s ease,background .18s ease}.next:hover{transform:translateY(-2px);border-color:rgba(134,241,193,.38);background:linear-gradient(135deg,rgba(134,241,193,.08),rgba(138,168,255,.05))}.next small{display:block;color:#748094;text-transform:uppercase;letter-spacing:.12em;font-size:9px;margin-bottom:3px}.next span{display:block;font-size:20px;font-weight:800;letter-spacing:-.025em}.next-arrow{flex:0 0 auto;width:42px;height:42px;border-radius:50%;display:grid;place-items:center;background:var(--accent);color:#07100d;font-size:23px;font-weight:900}.finish{border:1px solid rgba(134,241,193,.26);border-radius:18px;padding:20px;background:rgba(134,241,193,.05);margin-top:22px}.finish strong{font-size:20px}.finish p{color:#aab5c3}.finish a{color:var(--accent)}
.search-dialog{width:min(680px,calc(100vw - 28px));border:1px solid var(--line2);border-radius:22px;background:#0d1118;color:var(--text);padding:0;box-shadow:0 30px 100px rgba(0,0,0,.55)}.search-dialog::backdrop{background:rgba(0,0,0,.7);backdrop-filter:blur(6px)}.search-shell{padding:18px}.search-head{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:14px}.search-head>div{display:grid;gap:2px}.search-head small{font-size:9px;letter-spacing:.13em;text-transform:uppercase;color:var(--accent)}.search-head strong{font-size:20px}.search-head button{border:0;background:transparent;color:#8390a1;font-size:24px;cursor:pointer}.search-shell input{width:100%;border:1px solid var(--line2);background:#090c12;color:var(--text);border-radius:13px;padding:13px 14px;outline:none}.search-shell input:focus{border-color:var(--accent2)}.search-results{display:grid;gap:5px;max-height:48vh;overflow:auto;margin:12px 0}.search-result{display:flex;justify-content:space-between;gap:12px;border:1px solid transparent;border-radius:11px;padding:9px 10px;color:#e3e8ef;text-decoration:none}.search-result:hover{background:#131925;border-color:#283243}.search-result small{color:#718095}.search-hint{color:#697587}
@media(max-width:900px){.lesson{padding:calc(var(--header) + 28px) 18px 42px}.lesson-grid{grid-template-columns:1fr;gap:24px}.visual{position:static}.micro-grid{grid-template-columns:1fr}.micro-card.sre{grid-column:auto}.phase-subtitle{display:none}.picture pre{font-size:12px}.lesson h1{font-size:clamp(46px,13vw,72px)}}
@media(max-width:560px){:root{--header:58px}.site-header{padding:0 13px}.brand>span:last-child{display:none}.ghost-btn span{display:none}.lesson{padding-left:14px;padding-right:14px}.lesson h1{font-size:clamp(44px,15vw,64px)}.lesson:first-child h1{font-size:clamp(72px,28vw,124px)}.definition{font-size:19px}.visual-card{padding:14px}.next span{font-size:18px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.top-progress span,.next{transition:none}}