:root {
  --bg: #ffffff;
  --text: #1f2933;
  --muted: #5b6878;
  --accent: #0e7490;
  --line: #e2e8f0;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #070a0f;
    --text: #d8e0ea;
    --muted: #8996a8;
    --accent: #22d3ee;
    --line: #243040;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
main { max-width: 720px; margin: 0 auto; padding: 32px 16px 64px; }
h1 { font-size: 2rem; line-height: 1.2; margin: 8px 0; }
h2 { font-size: 1.25rem; margin-top: 2em; padding-top: 1em; border-top: 1px solid var(--line); }
h3 { font-size: 1.05rem; margin-bottom: 0.25em; }
a { color: var(--accent); }
code { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.9em; }
.nav, .meta { color: var(--muted); font-size: 0.9rem; }
.lead { font-size: 1.1rem; }