JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap">
  <div class="form">form</div>
</div>

CSS

html,body{margin:0;padding:0;height:100%;}
.wrap{text-align:center;height:100%;}
.wrap:after{content:'';display:inline-block;width:0;height:100%;vertical-align:middle;}
.form{display:inline-block;vertical-align:middle;}