html {
  box-sizing: border-box;
}

*,
*:before,
*:after {
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

html,
body,
canvas {
  width: 100%;
  height: 100%;
}

body {
  width: 100%;
  height: 100%;
  background-color: #222;
  position: relative;
  z-index: 0;
}
body:after {
  content: '';
  width: 100%;
  height: 100%;
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  background-color:rgba(0, 0, 0, 0.1);
  z-index: 1;
  -webkit-animation: thunder-bg 6s infinite;
          animation: thunder-bg 6s infinite;
}

canvas {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
}

#canvas3 {
  z-index: 5;
}

#canvas2 {
  z-index: 50;
}

#canvas1 {
  z-index: 100;
}

@-webkit-keyframes thunder-bg {
  0% {
    background-color: rgba(34, 34, 34, 0.9);
  }
  9% {
    background-color: rgba(34, 34, 34, 0.9);
  }
  10% {
    background-color: rgba(59, 59, 59, 0.3);
  }
  10.5% {
    background-color: rgba(34, 34, 34, 0.9);
  }
  80% {
    background-color: rgba(34, 34, 34, 0.9);
  }
  82% {
    background-color: rgba(59, 59, 59, 0.3);
  }
  83% {
    background-color: rgba(34, 34, 34, 0.9);
  }
  83.5% {
    background-color: rgba(59, 59, 59, 0.3);
  }
  100% {
    background-color: rgba(34, 34, 34, 0.9);
  }
}