:root {
  --bg: #ffffff;
  --ink: #1f2937;
  --muted: #6b7280;
  --link: #1d4ed8;
  --rule: #e5e7eb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111827;
    --ink: #e5e7eb;
    --muted: #9ca3af;
    --link: #93c5fd;
    --rule: #374151;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 system-ui, -apple-system, "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 12px; }
h2 { font-size: 1.15rem; margin: 32px 0 8px; padding-top: 16px; border-top: 1px solid var(--rule); }
.lead { font-size: 1.15rem; }
.muted, .crumb { color: var(--muted); font-size: 0.9rem; }
a { color: var(--link); }
ul { padding-left: 1.25rem; }
li { margin: 6px 0; }
code { font-size: 0.9em; }