:root {
  --bg-color: #fcfcf9;
  --text-color: #2c3e50;
  --link-color: #27ae60;
  --max-width: 800px;
}
body {
  font-family: system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 20px;
  background: var(--bg-color);
  color: var(--text-color);
}
header, footer { padding: 20px 0; }
h1, h2 { color: #1a252f; }
a { color: var(--link-color); text-decoration: none; }
a:hover { text-decoration: underline; }
form { margin: 20px 0; }
input { padding: 10px; width: 100%; max-width: 300px; }
button { padding: 10px 20px; cursor: pointer; }
@media (prefers-color-scheme: dark) {
  :root { --bg-color: #1a1a1a; --text-color: #e0e0e0; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}