JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">...</div>

CSS

#content {
    background-color: khaki; /* demo purposes */   
    position: absolute;    
    height: 20%;
    top: 50%;
    margin-top: -10%; /* half the height */    
    width: 30%;
    left: 50%;
    margin-left: -15%; /* half the width */
}