:root{color-scheme:dark;--bg:#09242d;--panel:#103641;--fg:#e9f4f7;--muted:#adc8d1;--accent:#4bdef0;--line:#37606d;--wrong:#ffb5bd;--correct:#9ce8c5}html.light{color-scheme:light;--bg:#f4f8fa;--panel:#fff;--fg:#163946;--muted:#466975;--accent:#006c7d;--line:#bacfd7;--wrong:#9b2137;--correct:#176446}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font:17px/1.6 system-ui,sans-serif}header,footer{max-width:960px;margin:auto;padding:24px;display:flex;justify-content:space-between;gap:20px}main{max-width:850px;margin:30px auto;padding:24px}h1{font-size:clamp(30px,5vw,48px);line-height:1.15}h2{line-height:1.3}.eyebrow{color:var(--accent);letter-spacing:.1em}fieldset{border:1px solid var(--line);border-radius:12px;background:var(--panel);padding:24px;margin:28px 0}legend{font-weight:650;padding:0 8px}label{display:flex;gap:14px;padding:14px 6px;cursor:pointer}input{flex-shrink:0}button{padding:12px 20px;border:1px solid var(--accent);border-radius:8px;background:var(--panel);color:var(--fg);font:inherit;cursor:pointer}button:disabled{opacity:.6;cursor:wait}:focus-visible{outline:3px solid var(--accent);outline-offset:4px}.wrong{color:var(--wrong)}.correct{color:var(--correct)}#review p{padding:16px;border:1px solid currentColor;border-radius:8px}footer{color:var(--muted);font-size:14px}[hidden]{display:none!important}