:root {
  --bg: #ffffff; --text: #1d1d1f; --muted: #6e6e73; --accent: #1a6cf0; --rule: #e5e5ea;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #000000; --text: #f5f5f7; --muted: #a1a1a6; --accent: #4c94ff; --rule: #2c2c2e; }
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
main { max-width: 720px; margin: 0 auto; padding: 40px 16px 64px; }
header { display: flex; align-items: center; gap: 14px; margin-bottom: 28px; }
header img { width: 56px; height: 56px; border-radius: 13px; }
header a { color: inherit; text-decoration: none; font-weight: 600; font-size: 22px; }
h1 { font-size: 32px; line-height: 1.2; margin: 0 0 6px; }
h2 { font-size: 21px; margin: 32px 0 8px; }
p, li { margin: 0 0 12px; }
ul { padding-left: 22px; }
a { color: var(--accent); }
.muted { color: var(--muted); font-size: 15px; }
nav { margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--rule); font-size: 15px; }
nav a { margin-right: 18px; }