:root{color-scheme:dark;--bg:#101c26;--panel:#1b2b36;--ink:#f3eddb;--muted:#c0cfd2;--mint:#91d4be;--gold:#f3bd66}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--bg);color:var(--ink);font:18px/1.6 system-ui,sans-serif}header{display:flex;justify-content:space-between;gap:24px;padding:20px 5%;border-bottom:1px solid #42545d;font-size:14px}a{color:var(--mint);text-underline-offset:5px}a:hover{color:white}main{max-width:1240px;margin:auto;padding:48px 28px}h1{font-size:clamp(36px,5vw,64px);line-height:1.1;max-width:900px;margin:14px 0 24px}h2{font-size:32px;line-height:1.25}h3{font-size:25px;line-height:1.35}.lead{font-size:23px;max-width:900px;color:var(--muted)}.eyebrow{color:var(--mint);font-weight:700;letter-spacing:.12em;font-size:13px}.steps{display:flex;flex-wrap:wrap;gap:20px;margin:30px 0}.steps a,.next{display:inline-block;padding:12px 20px;background:var(--panel);border-radius:9px}section{margin:50px 0 70px}video{width:100%;max-height:72vh;aspect-ratio:16/9;background:#09121a;border-radius:16px;display:block}.under{display:flex;flex-wrap:wrap;gap:24px;padding:16px 0;color:var(--muted);font-size:15px}details{margin:16px 0}summary{cursor:pointer;color:var(--mint)}#chapters{display:grid;grid-template-columns:1fr 1fr;gap:16px;padding-top:16px}#chapters article{background:var(--panel);padding:18px;border-radius:12px}#chapters p{font-size:16px}.controls{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:20px}label{display:block;margin:12px 0;font-weight:600}input,select,textarea{width:100%;display:block;margin-top:8px;padding:13px;border:1px solid #73868d;background:#14232e;color:var(--ink);font:inherit;border-radius:8px}textarea{min-height:100px;resize:vertical}.matrix-layout{display:grid;grid-template-columns:1fr 1fr;gap:40px;margin:36px 0}.layers{display:grid;gap:12px}.layers>div{position:relative;background:var(--panel);border:1px solid #537b7a;border-left:5px solid var(--mint);border-radius:8px;padding:14px 24px}.layers>div:not(:last-child):after{content:'↓';position:absolute;bottom:-24px;left:30px;color:var(--gold);z-index:1}.layers small{display:block;color:var(--muted);font-size:11px;letter-spacing:.14em}.layers .evidence{border-left-color:var(--gold)}.focus{padding:24px;background:#23353f;border-radius:12px}.note{color:var(--muted);font-size:15px;border-left:2px solid var(--gold);padding-left:16px}fieldset{border:1px solid #62757e;border-radius:12px;padding:20px}legend{font-weight:700;padding:0 12px}#choices label{display:flex;align-items:flex-start;gap:14px;font-weight:400;padding:12px;border-radius:8px;background:var(--panel)}#choices input{width:22px;height:22px;flex:none;accent-color:var(--mint)}button{font:inherit;cursor:pointer;padding:12px 18px;border:1px solid #62757e;background:var(--panel);color:var(--ink);border-radius:8px}button.primary{margin-top:20px;background:var(--mint);color:#10222c;border:0;font-weight:700}button:hover{filter:brightness(1.12)}:focus-visible{outline:3px solid var(--gold);outline-offset:4px}#feedback{min-height:70px;padding:20px;border-radius:8px;background:var(--panel)}footer{text-align:right;padding:28px 5%;color:var(--muted);font-size:14px}.skip{position:absolute;top:-100px}.skip:focus{top:4px;left:8px;background:var(--bg);padding:12px;z-index:10}@media(max-width:700px){header span{display:none}header{font-size:12px}.matrix-layout,#chapters{grid-template-columns:1fr}main{padding:24px 18px}.lead{font-size:20px}h2{font-size:27px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}