body {
  /* leave it to hide the scrollbars */
  overflow: hidden;
  /* background-color: black; */
  padding: 0; margin: 0;
}

canvas {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 50%;
  height: 50%;
  text-align: center;
}