body {
  background: #222;
  color: #fff;
  font-family: Arial, sans-serif;
  text-align: center;
  margin: 0;
  padding: 0;
}

h1 {
  margin: 20px 0 10px 0;
}

canvas#pong {
  background: #000;
  display: block;
  margin: 0 auto;
  border: 2px solid #fff;
  box-shadow: 0 0 20px #0008;
}