:root{--bg: #ffffff;--fg: #1a1a1a;--muted: #666;--line: #ddd;--accent: #9a2620;--accent-soft: #b4603c;--on-accent: #ffffff;--ok: #1a7f37;--bad: #b3261e}@media (prefers-color-scheme: dark){:root{--bg: #16181c;--fg: #e6e6e6;--muted: #9aa0a6;--line: #333;--accent: #e0736a;--accent-soft: #c9805f;--on-accent: #1a1a1a;--ok: #4ac26b;--bad: #ef6b63}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.6 system-ui,-apple-system,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif}main{max-width:46rem;margin:0 auto;padding:0 16px 4rem}header{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:1rem 0;border-bottom:1px solid var(--line)}header h1{font-size:1.25rem;margin:0}.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}.brand{display:flex;align-items:center;gap:.6rem;min-width:0}.brand img{height:34px;width:auto;display:block}@media (prefers-color-scheme: dark){.brand img{background:#fff;border-radius:6px;padding:3px 6px}}.brand .wordmark{display:block}@media (max-width: 420px){.brand .wordmark{display:none}.brand .emblem{display:block}}.brand .emblem{display:none;height:32px;width:auto}@media (prefers-color-scheme: dark){.brand .emblem{background:#fff;border-radius:6px;padding:2px}}nav{display:flex;gap:1rem;align-items:baseline;color:var(--muted)}.muted{color:var(--muted)}.error{color:var(--bad)}.ok{color:var(--ok)}.bad{color:var(--bad)}button{font:inherit;padding:.5rem 1rem;border:1px solid var(--accent);background:var(--accent);color:var(--on-accent);border-radius:6px;cursor:pointer}button:disabled{opacity:.5;cursor:not-allowed}button.secondary{background:transparent;color:var(--accent)}button.link{background:none;border:none;color:var(--accent);padding:0;text-decoration:underline}.alternatives{list-style:none;padding:0}.alt{display:block;padding:.6rem .8rem;margin:.4rem 0;border:1px solid var(--line);border-radius:6px;cursor:pointer}.alt.correct{border-color:var(--ok)}.alt .count{float:right}.feedback{border-top:1px solid var(--line);margin-top:1.5rem;padding-top:1rem}.explanation{white-space:pre-wrap}.login{max-width:22rem;margin:4rem auto;display:grid;gap:.75rem}.login-mark{width:100%;max-width:15rem;height:auto;margin:0 auto .5rem}@media (prefers-color-scheme: dark){.login-mark{background:#fff;border-radius:8px;padding:.5rem .75rem}}.login label{display:grid;gap:.25rem}.login .hint{font-size:.85em}.login input{font:inherit;padding:.5rem;border:1px solid var(--line);border-radius:6px;background:var(--bg);color:var(--fg)}.consent{border:1px solid var(--line);border-radius:8px;padding:1rem 1.25rem}.row{display:flex;gap:.75rem;flex-wrap:wrap}.courses{list-style:none;padding:0}.courses li{padding:.4rem 0}@media (max-width: 480px){main{padding:0 16px 3rem}}