html, body {
  margin: 0;
  padding: 0;
  background: black;
  overflow: hidden;
  height: 100%;
}

canvas {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: block;
  width: 80vw;
  height: 80vh;
}