/* Base */
* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  max-width: 800px;
  margin: 60px auto;
  padding: 0 24px;
  font-family: system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  color: #222;
  background: #fff;
}

/* Header */
header { margin-bottom: 48px; }
h1 { font-size: 1.5rem; font-weight: 600; margin-bottom: 4px; }
header p { color: #666; }

/* Columns */
main {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.column h2 {
  font-size: 0.875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #888;
  margin-bottom: 12px;
}

.column ul { list-style: none; }

.column li {
  padding: 4px 8px;
  margin: 0 -8px;
  border-radius: 4px;
}

.column a {
  color: inherit;
  text-decoration: none;
}

.column a:hover { text-decoration: underline; }

/* Selection state */
.column li.selected {
  background: #f0f0f0;
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  body { background: #111; color: #ddd; }
  header p { color: #888; }
  .column h2 { color: #666; }
  .column li.selected { background: #222; }
}

/* Articles */
article h1 {
  font-size: 1.5rem;
  margin-bottom: 16px;
}

article p {
  margin-bottom: 16px;
  max-width: 65ch;
}

article a { color: #0066cc; }

@media (prefers-color-scheme: dark) {
  article a { color: #6cf; }
}

/* Mobile: stack columns */
@media (max-width: 600px) {
  main {
    grid-template-columns: 1fr;
    gap: 24px;
  }
}