JSFiddle - React, Tailwind, and code Playground

HTML

<div class="mainwrapper" >
    <div class="innerwrapper">
    <div class="contentdiv">test</div>
    </div>
    </div>

CSS

body, html{height:100%;width:100%; margin:0}
.mainwrapper{display:table; width:100%; height:100%;}
.innerwrapper{display:table-cell; vertical-align:middle; text-align:center; height:100%;}
.contentdiv{width:50%;background:#ccc;margin:auto;}