:root {
  --bg: #ffffff;
  --fg: #1a1a1a;
  --muted: #555555;
  --border: #d8d8d8;
  --accent: #1a4d8f;
  --max-width: 760px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --fg: #f0f0f0;
    --muted: #b8b8b8;
    --border: #3a3a3a;
    --accent: #7fb0ff;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
}

header, main, footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem 1rem;
}

header {
  border-bottom: 1px solid var(--border);
}

h1 {
  margin: 0 0 0.25rem 0;
  font-size: 1.75rem;
}

.tagline {
  margin: 0 0 1rem 0;
  color: var(--muted);
}

nav ul {
  list-style: none;
  display: flex;
  gap: 1.25rem;
  padding: 0;
  margin: 0;
}

nav a {
  color: var(--accent);
  text-decoration: none;
}

nav a:hover, nav a:focus {
  text-decoration: underline;
}

h2 {
  font-size: 1.35rem;
  margin-top: 2rem;
}

.cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 600px) {
  .cards {
    grid-template-columns: 1fr 1fr;
  }
}

.card {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1rem;
}

.card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1.1rem;
}

.card p {
  margin: 0.4rem 0;
}

.demonstrates {
  color: var(--muted);
  font-size: 0.95rem;
}

.meta {
  font-size: 0.85rem;
  color: var(--muted);
}

.label {
  display: inline-block;
  padding: 0.1rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 0.8rem;
}

footer {
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
}

a {
  color: var(--accent);
}
header h1 { font-size: clamp(2.3rem, 7vw, 4rem); letter-spacing: -.045em; } .tagline { font-size: 1.25rem; } nav ul { flex-wrap: wrap; } @media print { nav { display: none; } .card { break-inside: avoid; } }