body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background-color: #f0f0f0;
}

canvas {
  display: block;
  margin: 0 auto;
  background-color: #d0d0d0;
  border: 2px solid #333;
}

input, button {
  display: block;
  margin: 10px auto;
  padding: 10px;
  font-size: 16px;
}