body {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0;
  overflow: hidden;
}

#container {
  position: absolute;
  width: 100vmax;
  height: 100vmax;
  left: 50%;
  top: 50%;
  background: linear-gradient(to bottom, #000, #111);
  transform: translate3d(-50%, -40%, 0);
}

canvas {
  display: block;
}