JSFiddle - React, Tailwind, and code Playground

HTML

<video id="video">
    <source src="http://techslides.com/demos/sample-videos/small.mp4" type="video/mp4">
    Your browser does not support HTML5 video.
</video>

CSS

#video {
    position: fixed;
    left: 0;
    top: 0;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
}