JSFiddle - React, Tailwind, and code Playground

HTML

<video width="100%" height="auto" autoplay loop id="video_startpage" >
  <source src="https://a0.muscache.com/airbnb/static/Croatia-P1-1.mp4" type="video/mp4">

</video><!-- /video -->

CSS

#video_startpage {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  z-index: -1000;
  min-width:100%;
  max-height:300px;
  
}