:root{color-scheme:dark;--bg:#091416;--panel:#102224;--ink:#e8f4ef;--muted:#a7c2bd;--accent:#99edc8;--line:#284745;font:16px/1.6 system-ui,sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink)}header,main,footer,nav{max-width:1120px;margin:auto;padding:24px}header{display:flex;justify-content:space-between;gap:20px;align-items:center;border-bottom:1px solid var(--line);padding-top:40px}h1{font-size:clamp(2rem,6vw,3.5rem);line-height:1.1;margin:10px 0}h2{font-size:1.8rem;line-height:1.3}h3{margin-top:0}.eyebrow{letter-spacing:.18em;font-size:.72rem;color:var(--accent);font-weight:700}p{color:var(--muted)}nav{display:flex;flex-wrap:wrap;gap:8px;position:sticky;top:0;background:var(--bg);z-index:2;border-bottom:1px solid var(--line);padding-block:14px}button,input,select{font:inherit;border:1px solid var(--line);border-radius:10px;padding:10px 14px;background:var(--panel);color:var(--ink)}button{cursor:pointer;min-height:44px}button:hover,button[aria-current=page]{border-color:var(--accent);color:var(--accent)}button:disabled{opacity:.5;cursor:wait}button.primary{background:var(--accent);color:#102224;font-weight:700}button:focus-visible,input:focus-visible,a:focus-visible{outline:3px solid #ffd991;outline-offset:3px}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}.card{background:var(--panel);border:1px solid var(--line);padding:22px;border-radius:16px;min-width:0}.card p{margin-bottom:16px}.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}.stack{display:grid;gap:12px}.notice{border-left:3px solid var(--accent);padding:12px 18px;background:var(--panel);margin:20px 0}.badge{font-size:.75rem;color:var(--accent);text-transform:uppercase;letter-spacing:.08em}pre{white-space:pre-wrap;overflow-wrap:anywhere;background:#071012;border:1px solid var(--line);padding:16px;border-radius:12px;font:14px/1.65 ui-monospace,monospace}input[type=search]{width:100%;margin-bottom:20px}label{display:block;color:var(--muted)}a{color:var(--accent)}footer{display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px;font-size:.78rem;color:var(--muted);border-top:1px solid var(--line)}details{margin:12px 0;border:1px solid var(--line);padding:14px;border-radius:10px}summary{cursor:pointer;font-weight:600}.skip{position:absolute;top:-100px}.skip:focus{top:10px;background:var(--panel);padding:12px;z-index:10}.answer{width:100%;text-align:left}.answer.correct{border-color:var(--accent)}.answer.wrong{border-color:#ffad9b}.result{font-weight:600;color:var(--accent)}@media(max-width:600px){header,main,footer,nav{padding:16px}nav{position:static}header{align-items:flex-start}nav button{font-size:.88rem;flex:1 0 auto}.grid{grid-template-columns:1fr}h1{font-size:2.3rem}}@media(prefers-reduced-motion:no-preference){button{transition:border-color .15s}}