:root{--bg:#f6f8fa;--card:#fff;--ink:#0d1b2a;--muted:#5b6b7a;--accent:#0e7480}
@media (prefers-color-scheme:dark){:root{--bg:#0a1c33;--card:#10263f;--ink:#eef3f7;--muted:#9fb0bf;--accent:#33cccc}}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 -apple-system,system-ui,sans-serif}
main{max-width:720px;margin:0 auto;padding:32px 16px 64px}h1{font-size:28px;margin:0 0 4px}h2{font-size:19px;margin:28px 0 8px}
.muted{color:var(--muted)}.card{background:var(--card);border-radius:14px;padding:18px 20px;margin:14px 0}a{color:var(--accent)}
nav{display:flex;gap:16px;margin-bottom:24px;font-weight:600}