JSFiddle - React, Tailwind, and code Playground

by loginet

HTML

<div class="exactCenter"></div>

CSS

.exactCenter {
    width:200px;
    height:200px;
    position: fixed;
    background-color: #00FF00;
    top: 50%;
    left: 50%;
    margin-top: -100px;
    margin-left: -100px;
}