:root { --bg: #f6f8f9; --fg: #16222a; --muted: #5b6b75; --accent: #0a7fa3; --card: #ffffff; --line: #dde4e8; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #071820; --fg: #e8f1f4; --muted: #9db0ba; --accent: #4cc8ec; --card: #0d2530; --line: #1c3a47; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; }
main { max-width: 720px; margin: 0 auto; padding: 48px 16px 64px; }
h1 { font-size: 2rem; line-height: 1.2; margin: 0 0 4px; }
h2 { font-size: 1.3rem; margin: 40px 0 8px; padding-top: 24px; border-top: 1px solid var(--line); }
.muted { color: var(--muted); }
a { color: var(--accent); }
nav { display: flex; gap: 16px; margin-bottom: 32px; font-weight: 600; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px 20px; margin: 16px 0; }
ul { padding-left: 22px; }