body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #fafafa;
  color: #111;
}

header {
  padding: 20px 0;
  text-align: center;
}

nav a {
  margin: 0 10px;
  text-decoration: none;
  color: #333;
  font-weight: 500;
}

nav a.active {
  color: #000;
  border-bottom: 2px solid #000;
}

main {
  max-width: 720px;
  margin: 40px auto;
  padding: 0 16px;
  text-align: left;
}

h1 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.desc {
  color: #555;
  margin-bottom: 32px;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.card {
  display: block;
  border: 1px solid #eee;
  border-radius: 12px;
  padding: 20px;
  background: #fff;
  transition: all 0.2s ease;
}

.card:hover {
  border-color: #ccc;
  transform: translateY(-3px);
}

footer {
  text-align: center;
  color: #777;
  font-size: 14px;
  margin: 60px 0 20px;
}