body {
  text-align: center;
  font-family: Arial, sans-serif;
  background: #111;
  color: #fff;
}

canvas {
  margin: 20px auto;
  display: block;
}

button {
  padding: 12px 30px;
  font-size: 18px;
  background: gold;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

button:disabled {
  background: gray;
}