:root { --bg: #ffffff; --fg: #1a1a1a; --muted: #666; --link: #2457d6; }
@media (prefers-color-scheme: dark) { :root { --bg: #111; --fg: #e8e8e8; --muted: #999; --link: #8ab4ff; } }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg);
  font: 16px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
main { max-width: 680px; margin: 0 auto; padding: 48px 16px 24px; }
footer { max-width: 680px; margin: 0 auto; padding: 16px 16px 48px; color: var(--muted); font-size: 14px; }
h1 { font-size: 2rem; margin: 0 0 16px; }
h2 { font-size: 1.15rem; margin: 32px 0 8px; }
a { color: var(--link); }
.muted { color: var(--muted); }
code { font-size: 0.9em; }