body {
  margin: 0;
  padding: 0;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: black;
}

canvas {
  width="800";
  height="800";
  style="position: absolute; top:0%; left: 0%; width: 100%;"
  max-width: 100%;
  max-height: 100%;
}