canvas {
  display: block;
  margin: 2em;
}
.bg-canvas {
  position: fixed;
  top: 0;
  left: 0;
  z-index: -1;
  width: 100%;
  height: 100%;
  margin: 0;
}
body {
  background-image: -webkit-gradient(linear, left bottom, left top, color-stop(40%, #d7dde6), color-stop(80%, #97a8c0));
  background-image: linear-gradient(to top, #d7dde6 40%, #97a8c0 80%);
  background-size: cover;
  width: 400vw;
  height: 400vh;
}