JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer">I'm partially hidden. Change the opacity of fade to a higher value to prove it
    <div class="fade">
        <div class="inner">testing testing</div>
    </div>
</div>

CSS

.outer { position: relative; z-index: 2; }
.inner { background: rgba(255,255,255,1); left: 50px; position: fixed; top: 40px; }
.fade { background: rgba(92,92,92,.5); bottom: 0; left: 0; position: fixed; right: 0; top: 0; }