:root {
  color-scheme: light dark;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --bg: #ffffff;
  --rule: #d2d2d7;
  --link: #0066cc;
}
@media (prefers-color-scheme: dark) {
  :root {
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --bg: #000000;
    --rule: #424245;
    --link: #2997ff;
  }
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "PingFang HK", "PingFang TC", "Helvetica Neue", sans-serif;
}
main {
  max-width: 680px;
  margin: 0 auto;
  padding: 32px 16px 64px;
}
h1 { font-size: 28px; line-height: 1.3; margin: 0 0 8px; }
h2 { font-size: 20px; margin: 32px 0 8px; }
a { color: var(--link); }
.meta, .nav { color: var(--muted); font-size: 15px; }
.nav { margin: 0 0 24px; }
hr { border: 0; border-top: 1px solid var(--rule); margin: 56px 0; }
dt { font-weight: 600; margin-top: 16px; }
dd { margin: 4px 0 0; }
ul, ol { padding-left: 24px; }