Use youtube video as background

Just a cute video background

* { box-sizing: border-box; }
.video-background {
  background: #000;
  position: fixed;
  top: 0; right: 0; bottom: 0; left: 0;
  z-index: -99;
}
.video-foreground,
.video-background iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
@media (min-aspect-ratio: 16/9) {
  .video-foreground { height: 300%; top: -100%; }
}
@media (max-aspect-ratio: 16/9) {
  .video-foreground { width: 300%; left: -100%; }
}

<div class="video-background">
    <div class="video-foreground">
      <iframe src="https://www.youtube.com/embed/fkaekKxfSc4?controls=0&showinfo=0&rel=0&autoplay=1&loop=1&playlist=W0LHTWG-UmQ" frameborder="0" allowfullscreen></iframe>
    </div>
</div>