body {
  background: #222;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}

canvas {
  background: #111;
  display: block;
  margin: 40px auto 0 auto;
  border: 2px solid #eee;
  box-shadow: 0 0 20px #000a;
}