JSFiddle - React, Tailwind, and code Playground

HTML

<iframe width="560" height="315" src="https://youtube.com/embed/p0O1VVqRSK0?wmode=transparent" wmode="Opaque" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
<div id="overlay">
  Overlay
</div>

CSS

#overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 200px;
  height: 200px;
  background: yellow;
  border: 2px solid red;
  z-index: 2
}