:root {
  --bg: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --line: #e5e5ea;
  --link: #0066cc;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --line: #2c2c2e;
    --link: #4da3ff;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
main {
  max-width: 680px;
  margin: 0 auto;
  padding: 64px 16px;
}
header { margin-bottom: 40px; }
header a { color: var(--text); text-decoration: none; font-weight: 600; }
h1 { font-size: 40px; line-height: 1.15; margin: 0 0 16px; letter-spacing: -0.02em; }
h2 { font-size: 20px; margin: 32px 0 8px; }
p, li { color: var(--text); }
.muted { color: var(--muted); }
a { color: var(--link); }
footer {
  margin-top: 64px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}
footer nav a { margin-right: 16px; }