JSFiddle - React, Tailwind, and code Playground

HTML

<div id="underground"></div>
<div id="overlay">
</div>

CSS

#underground {
		background-color: black;
		position: absolute;
		top: 0;
		left: 0;
		bottom: 0;
		right: 0;	
	}
	#overlay {
	    width: 100px;
        height: 100px;
        border: 300px solid red;
		position: absolute;
		top: 0;
		left: 0;
		bottom: 0;
		right: 0;
		overflow: hidden;	
	}