:root{color-scheme:light dark;--fg:#1d2430;--muted:#5b6575;--bg:#f7f8fa;--card:#fff;--accent:#2563a8;--line:#e2e6ec}
@media (prefers-color-scheme:dark){:root{--fg:#e6e9ee;--muted:#9aa4b2;--bg:#12161c;--card:#1a2029;--accent:#7fb0e8;--line:#2a323d}}
*{box-sizing:border-box}
body{margin:0;font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;color:var(--fg);background:var(--bg)}
main{max-width:720px;margin:0 auto;padding:48px 20px 64px}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:28px 32px;margin-bottom:24px}
h1{font-size:1.9rem;margin:0 0 4px}
h2{font-size:1.2rem;margin:28px 0 8px}
.card h2:first-child{margin-top:0}
.sub{color:var(--muted);margin:0 0 24px}
a{color:var(--accent)}
nav{margin-bottom:24px;font-size:.95rem}
nav a{margin-right:16px}
ul{padding-left:1.2rem}
footer{color:var(--muted);font-size:.9rem;text-align:center}
.lang{color:var(--muted);font-size:.8rem;text-transform:uppercase;letter-spacing:.08em;margin:0 0 8px}