JSFiddle - React, Tailwind, and code Playground

HTML

<div class="coverer-container">
    <div class="coverer">
        <p>I want this to have an opaque background.</p>
    </div>
</div>
<div class="coveree">
    <p>So you can not see this text.</p>
</div>

CSS

.coverer-container{
    position:relative;
    height:0;
    width:0;
    overflow:visible;
}

.coverer{
    position:absolute;
    height:300px;
    width:300px;
    background:white;
}