* {
  box-sizing: border-box;
}

body {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: black;
}

#overlay {
  position: absolute;
  width: 100%;
  height: 100%;
  z-index: 0;
  background-color: rgba(0, 0, 0, 0.5);
  transition: 3s;
}

#canvas {
  position: absolute;
  width: 100%;
  height: 100%;
}