JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block"></div>

CSS

.block {
    width: 50%;
    height: 40px;
    
    position: relative;
    margin: 40px auto;
}

.block:after {
    content: '';
    
    position: absolute;
    top: 0;       left: -9999px;
    bottom: 0;    right: 0;
    
    background: #000;
}