JSFiddle - React, Tailwind, and code Playground

HTML

<div id="child"></div>

CSS

html, body {
  margin: 0;
  height: 100%;
}

#child {
  width: 200px;
  height: 200px;
  background: black;
}

body {
  font-size: 0;
  line-height: 100vh;
}

#child {
  display: inline-block;
  vertical-align: middle;
}