JSFiddle - React, Tailwind, and code Playground

HTML

<iframe class="youtube-player" type="text/html" width="520" height="330" src="http://www.youtube.com/embed/Lk_WoaLUPdA&autoplay=1&autoplay=1" frameborder="0"></iframe>
<div id="overlay">overlay</div>

CSS

#overlay {
    position:fixed;
    top:0;
    left:0;
    width:50px;height:50px;
    background:#000;
    /*background:rgba(255,255,255,0.8); or just this*/
    z-index:9999;
    color:#fff;
    opacity:0.8;
    pointer-events: none;
}