:root {
  --bg-color: #ffffff;
  --text-color: #333333;
  --link-color: #005a8d;
  --spacing: 1.5rem;
}
@media (prefers-color-scheme: dark) {
  :root { --bg-color: #1a1a1a; --text-color: #f0f0f0; --link-color: #70b3e0; }
}
body {
  font-family: system-ui, sans-serif;
  line-height: 1.6;
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing);
  background: var(--bg-color);
  color: var(--text-color);
}
header, footer { padding: 1rem 0; }
nav a { margin-right: 1rem; color: var(--link-color); text-decoration: none; }
nav a:hover { text-decoration: underline; }
a { color: var(--link-color); }
button, input { padding: 0.75rem; font-size: 1rem; margin-top: 0.5rem; }
textarea { width: 100%; height: 150px; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }