JSFiddle - React, Tailwind, and code Playground

HTML

<html>

<body>
<div id="overload"> </div>
<div class="test">Teesting </div>
</body>
</html>

CSS

#overload {
    background-color:black;
	opacity:0.6;
    position:fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
     color:#FFFFFF;  
	}
	.test {
	width:50px; height:50px; background-color:white; color black; z-index:1000;
	}