:root{color-scheme:dark;--bg:#050914;--panel:#0d1627;--panel2:#121f34;--text:#edf4ff;--muted:#9eacc2;--line:#273650;--cyan:#22d3ee;--violet:#8b5cf6;--gold:#f5c35b;--ok:#34d399;--danger:#fb7185;--shadow:0 24px 70px rgba(0,0,0,.33)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:radial-gradient(950px 520px at 100% -5%,rgba(139,92,246,.18),transparent 62%),radial-gradient(760px 440px at -5% 6%,rgba(34,211,238,.11),transparent 60%),var(--bg);color:var(--text);font:16px/1.62 Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif}.shell{width:min(1180px,calc(100% - 32px));margin-inline:auto}a{color:inherit}.skip-link{position:fixed;left:12px;top:-80px;background:white;color:#111;padding:10px 14px;z-index:200;border-radius:8px}.skip-link:focus{top:12px}.topbar{position:sticky;top:0;z-index:100;border-bottom:1px solid var(--line);background:rgba(5,9,20,.9);backdrop-filter:blur(18px)}.topbar-inner{min-height:68px;display:flex;align-items:center;justify-content:space-between;gap:20px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none}.brand-mark{display:grid;place-items:center;width:42px;height:42px;border-radius:14px;background:linear-gradient(145deg,var(--cyan),var(--violet));font-weight:950}.brand strong{display:block}.brand small{display:block;color:var(--muted)}.topnav{display:flex;flex-wrap:wrap;gap:8px}.topnav a,.topnav button{border:1px solid var(--line);background:var(--panel);color:var(--text);border-radius:999px;padding:8px 12px;text-decoration:none;font:inherit;font-weight:800;cursor:pointer}.topnav a:hover,.topnav button:hover{border-color:var(--cyan)}.hero{padding:72px 0 36px;display:grid;grid-template-columns:minmax(0,1.45fr) minmax(300px,.7fr);gap:28px;align-items:center}.eyebrow{color:var(--cyan);font-size:.76rem;letter-spacing:.16em;text-transform:uppercase;font-weight:950}.hero h1{font-size:clamp(2.7rem,7vw,6rem);line-height:.95;margin:12px 0 20px}.lead{font-size:clamp(1.05rem,2vw,1.3rem);color:var(--muted);max-width:800px}.hero-tags,.hero-actions,.chips,.control-row{display:flex;gap:9px;flex-wrap:wrap}.hero-tags span{border:1px solid var(--line);background:rgba(13,22,39,.7);border-radius:999px;padding:6px 10px;color:var(--muted);font-size:.86rem;font-weight:800}.hero-actions{margin-top:26px}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:44px;border:1px solid var(--line);border-radius:13px;padding:10px 15px;text-decoration:none;background:var(--panel);color:var(--text);font:inherit;font-weight:850;cursor:pointer}.btn.primary{border-color:transparent;background:linear-gradient(135deg,var(--cyan),var(--violet));color:white}.btn.compact{min-height:40px;padding:8px 11px}.btn:hover{transform:translateY(-1px);outline:2px solid rgba(34,211,238,.24);outline-offset:2px}.hero-card{border:1px solid rgba(245,195,91,.38);background:linear-gradient(155deg,rgba(245,195,91,.13),rgba(13,22,39,.92));padding:24px;border-radius:24px;box-shadow:var(--shadow)}.hero-card-kicker{color:var(--gold);font-size:.8rem;letter-spacing:.13em;font-weight:950;text-transform:uppercase}.hero-card strong{display:block;font-size:1.42rem;line-height:1.2;margin:10px 0}.hero-card p{color:var(--muted);margin-bottom:0}.progress-panel{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:18px;padding:18px 20px;border:1px solid var(--line);border-radius:18px;background:var(--panel)}.progress-panel strong{display:block}.progress-track{height:10px;border-radius:999px;background:#17243a;overflow:hidden}.progress-track span{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--cyan),var(--violet));transition:width .25s}.text-btn{border:0;background:none;color:var(--muted);font:inherit;font-weight:800;cursor:pointer}.intro-grid,.final-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:18px;padding-top:32px}.panel{border:1px solid var(--line);border-radius:22px;padding:24px;background:linear-gradient(160deg,var(--panel),var(--panel2));box-shadow:var(--shadow)}.panel h2,.controls h2{font-size:clamp(1.7rem,4vw,2.6rem);margin:5px 0 12px}.panel p{color:var(--muted)}.route{display:grid;gap:9px;margin-top:20px}.route span{display:flex;align-items:center;gap:10px;padding:9px 11px;border:1px solid var(--line);border-radius:12px;background:rgba(5,9,20,.35)}.route i{width:10px;height:10px;border-radius:50%;background:var(--c);box-shadow:0 0 18px var(--c)}.controls{padding-top:50px}.controls>div:first-child p{color:var(--muted);margin-top:0}.control-row{align-items:center;margin:20px 0 12px}.search{flex:1;min-width:280px;display:flex;align-items:center;gap:8px;border:1px solid var(--line);background:var(--panel);border-radius:14px;padding:0 13px}.search input{width:100%;height:44px;border:0;outline:0;background:transparent;color:var(--text);font:inherit}.control-row select{min-height:44px;border:1px solid var(--line);border-radius:13px;background:var(--panel);color:var(--text);padding:0 12px;font:inherit;font-weight:800}.filter-chip{--chip:var(--cyan);border:1px solid var(--line);background:var(--panel);color:var(--muted);padding:7px 11px;border-radius:999px;font:inherit;font-size:.83rem;font-weight:850;cursor:pointer}.filter-chip:before{content:"";display:inline-block;width:7px;height:7px;border-radius:50%;background:var(--chip);margin-right:7px}.filter-chip.active{border-color:var(--chip);color:var(--text);box-shadow:0 0 0 2px color-mix(in srgb,var(--chip) 18%,transparent)}.question-list{display:grid;gap:14px;padding-top:20px}.question{--block:#38bdf8;border:1px solid var(--line);border-left:4px solid var(--block);border-radius:19px;background:linear-gradient(160deg,var(--panel),var(--panel2));overflow:hidden}.question[hidden]{display:none}.q-head{width:100%;display:grid;grid-template-columns:55px 1fr auto;gap:15px;align-items:center;text-align:left;border:0;background:transparent;color:inherit;padding:19px 20px;cursor:pointer}.q-num{display:grid;place-items:center;width:44px;height:44px;border-radius:13px;background:color-mix(in srgb,var(--block) 16%,var(--panel));color:var(--block);font-weight:950}.q-title small{display:block;color:var(--block);font-weight:900;text-transform:uppercase;letter-spacing:.08em;font-size:.7rem}.q-title strong{display:block;font-size:1.12rem;line-height:1.35;margin-top:3px}.q-chevron{color:var(--muted);font-size:1.25rem;transition:transform .2s}.question.open .q-chevron{transform:rotate(180deg)}.answer{display:none;border-top:1px solid var(--line);padding:0 20px 20px}.question.open .answer{display:block}.answer-section{margin-top:20px}.answer-section h4{margin:0 0 8px;font-size:.78rem;letter-spacing:.12em;text-transform:uppercase;color:var(--block)}.answer-section p{margin:7px 0;color:#d8e4f5}.answer-section ul{margin:8px 0 0;padding-left:20px;color:#d8e4f5}.answer-section.callout{padding:16px;border-radius:14px;background:color-mix(in srgb,var(--block) 8%,rgba(5,9,20,.6));border:1px solid color-mix(in srgb,var(--block) 28%,var(--line))}.q-footer{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;border-top:1px dashed var(--line);margin-top:18px;padding-top:14px}.mastery{border:1px solid var(--line);background:#0a1220;color:var(--muted);border-radius:999px;padding:8px 12px;font:inherit;font-weight:850;cursor:pointer}.mastery.is-mastered{border-color:var(--ok);color:var(--ok);background:rgba(52,211,153,.08)}.q-index{color:var(--muted);font-size:.85rem}.empty-state{text-align:center;padding:50px 0}.final-grid{padding-top:48px}.checklist{padding-left:0;list-style:none;display:grid;gap:10px}.checklist li{padding:10px 12px 10px 38px;position:relative;border:1px solid var(--line);border-radius:12px;color:#d8e4f5}.checklist li:before{content:"✓";position:absolute;left:12px;color:var(--ok);font-weight:950}.sources{padding:24px 0 60px}.sources details{border:1px solid var(--line);border-radius:16px;background:var(--panel);padding:16px 18px}.sources summary{cursor:pointer;font-weight:900}.sources li{margin:7px 0;color:var(--muted)}footer{border-top:1px solid var(--line);padding:30px 0 46px;color:var(--muted)}.toast{position:fixed;right:18px;bottom:18px;max-width:330px;background:#111c30;color:white;border:1px solid var(--line);border-radius:13px;padding:11px 14px;box-shadow:var(--shadow);opacity:0;transform:translateY(12px);pointer-events:none;transition:.2s}.toast.show{opacity:1;transform:none}body.light{color-scheme:light;--bg:#f6f8fc;--panel:#fff;--panel2:#f4f7fb;--text:#132036;--muted:#5c6c82;--line:#d5deea;--shadow:0 18px 50px rgba(41,58,85,.11)}body.light{background:radial-gradient(900px 500px at 100% 0,rgba(139,92,246,.08),transparent 60%),var(--bg)}body.light .topbar{background:rgba(246,248,252,.9)}body.light .answer-section p,body.light .answer-section ul{color:#31415a}body.light .mastery{background:#f7f9fc}.floating-focus{animation:pulseFocus 1.1s ease}@keyframes pulseFocus{0%,100%{box-shadow:none}50%{box-shadow:0 0 0 5px rgba(34,211,238,.24)}}
@media(max-width:800px){.topbar{position:relative}.topbar-inner{align-items:flex-start;padding-block:12px}.topnav{justify-content:flex-end}.hero,.intro-grid,.final-grid{grid-template-columns:1fr}.hero{padding-top:46px}.progress-panel{grid-template-columns:1fr}.q-head{grid-template-columns:46px 1fr auto;padding:16px 14px}.q-title strong{font-size:1rem}.shell{width:min(100% - 22px,1180px)}}
@media print{.topbar,.hero-actions,.progress-panel,.controls,.mastery,.q-footer,.toast{display:none!important}body{background:white;color:#111}.shell{width:100%}.hero{display:block;padding:10px 0}.hero-card{box-shadow:none}.question{break-inside:avoid;border:1px solid #bbb;margin-bottom:10px}.answer{display:block!important}.q-head{cursor:default}.q-chevron{display:none}.answer-section p,.answer-section ul,.panel p{color:#222}.panel{box-shadow:none}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}