JSFiddle - React, Tailwind, and code Playground

HTML

<div id="below">
    <p>Line 1 </p>
    <p>Line 2 </p>
    <p>Line 3 </p>
    <p>Line 4 </p>
    <p>Line 5 </p>
    <p>Line 6 </p>
    <p>Line 7 </p>
    <p>Line 8 </p>
    <p>Line 9 </p>
    <p>Line 10 </p>
    <p>Line 11 </p>
    <p>Line 12 </p>
    <p>Line 13 </p>
    <p>Line 14 </p>
    <p>Line 15 </p>
</div>

<div id="above"></div>

CSS

#below {
    width: 200px;
    height: 200px;
    overflow: auto;
}

#above {
    position: absolute;
    top: 50px;
    width: 300px;
    height: 50px;
    background-color: red;
    
    /* shouldn't be needed, but doesn't help either */
    z-index: 100;
}