body {
  margin: 0;
  background: #111;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  font-family: sans-serif;
  color: #fff;
  flex-direction: column;
}

canvas {
  background: #eee;
  border: 2px solid #333;
}

#startScreen {
  text-align: center;
}

#startButton {
  padding: 10px 20px;
  font-size: 16px;
  cursor: pointer;
}