body {
  font-family: system-ui, sans-serif;
  margin: 0;
  background: #0a0a0a;
  color: #f1f1f1;
  text-align: center;
}

header {
  padding: 100px 20px;
  background: linear-gradient(45deg, #111, #1a1a1a);
}

h1 {
  font-size: 3em;
  color: #00ff88;
}

.btn {
  display: inline-block;
  padding: 12px 24px;
  background: #00ff88;
  color: #000;
  border-radius: 6px;
  text-decoration: none;
  font-weight: bold;
}

section {
  padding: 50px 20px;
}

.card {
  display: inline-block;
  background: #111;
  margin: 15px;
  padding: 20px;
  border-radius: 8px;
  width: 220px;
}

footer {
  background: #111;
  padding: 30px;
  font-size: 0.9em;
  color: #888;
}