html, body {
  width: 100%;
  height: 100%;
  margin: 0;
}
body {
  background: #000;
  padding: 0;
  overflow: hidden;
}
canvas {
  display: block;
  margin: auto;
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
}

#defaultCanvas0 {
  z-index:1;
}
#defaultCanvas1 {
   z-index: -1;
   opacity: 0;
  /* display: none;  */
}