this will make a video cover the full screen of the browser no matter what size it is. It will do some cropping to make it fit.

<style>
body, html {
	margin:0;
	padding:0;
}
.video-container {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 100%;
  height: 100%; 
  overflow: hidden;
}
.video-container video {
  min-width: 100%; 
  min-height: 100%; 
  width: auto;
  height: auto;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%,-50%);
}
</style>

<div class='video-container'>
	<video id="desk" loop autoplay>
		<source src="video/blurred-bokeh-video.webm" type="video/webm">
	</video>
</div>

Full Screen Example