.body {
  /* set margin to 0 and overflow to hidden, to go fullscreen */
  /* margin-top: 20px; */
  /* overflow: hidden; */
}

#button{
  position: absolute;
  top:  0px;
  left: 0px;
}

#canvas{
  position: absolute;
  top: 0px;
  left: 0px;
  z-index: -1;
}
