body {
  max-width: 640px;
  margin: 3rem auto;
  padding: 0 1.25rem;
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #1d1d1f;
}
h1 { font-size: 1.5rem; }
h2 { font-size: 1.15rem; margin-top: 2rem; }
a { color: #b06f14; }
footer { margin-top: 3rem; font-size: 0.85rem; color: #6e6e73; }
@media (prefers-color-scheme: dark) {
  body { background: #1c1c1e; color: #f2f2f7; }
  a { color: #e0952c; }
  footer { color: #98989d; }
}