JSFiddle - React, Tailwind, and code Playground

HTML

<div class="center">
    <div class="box" style="width:50px; height: 50px;"></div>
</div>

CSS

.center {
    display: table;
}

.box	{
	display: table-cell;
	position: absolute;
	vertical-align: middle;
	left: 0;
	right: 0;
	bottom: 0;
	top: 0;
	margin: auto;
    background: red;
}