body {
  background: #0f172a;
  color: #e5e7eb;
  text-align: center;
  font-family: Arial, sans-serif;
}

.buttons button {
  width: 80px;
  height: 80px;
  margin: 10px;
  border: none;
  border-radius: 8px;
}

.red { background: red; }
.green { background: green; }
.blue { background: blue; }
.yellow { background: gold; }