body {
  margin: 0;
  background: #f5f5f5;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-top: 20px;
  font-family: Arial, sans-serif;
}

.controls {
  margin-bottom: 12px;
}

button {
  padding: 10px 18px;
  font-size: 16px;
  cursor: pointer;
  margin-right: 6px;
}

canvas {
  background: white;
  border: 1px solid #ccc;
}