body {
  /* background-image: url("background.gif");
  background-repeat: no-repeat;
  background-size: cover; */
  background-color: grey;
  margin: 0;
  padding: 0;
  width: 100vw;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}
canvas {
  border: 1px solid white;
  position: absolute;
}