:root {
  --bg: #ffffff;
  --text: #1f1f1f;
  --muted: #666666;
  --link: #1a4f8b;
  --line: #e2e2e2;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161616;
    --text: #e8e8e8;
    --muted: #a0a0a0;
    --link: #8bb8ec;
    --line: #333333;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.55;
}
main {
  max-width: 640px;
  margin: 0 auto;
  padding: 48px 16px 64px;
}
h1 { font-size: 1.8rem; margin: 0 0 1.5rem; }
h2 { font-size: 1rem; margin: 1.8rem 0 0.3rem; }
p { margin: 0; }
a { color: var(--link); }
ul { padding-left: 1.2rem; margin: 0.3rem 0 0; }
footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}
footer a { margin-right: 1rem; }