JSFiddle - React, Tailwind, and code Playground

HTML

<div id="someId"></div>

CSS

#someId{
    width: 100px;
    height: 100px;
    padding: 0;
    border: 0;

    margin-left:-50px; /* 100/2 */
    margin-top:-50px; /* 100/2 */

    position: absolute;
    left: 50%;
    top: 50%;

    background:#000;
    z-index: 2500;
    
    box-shadow:0 0 150px #000;
}