JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
  Hello, I'm centered :D
</div>

CSS

html, 
body {
  height: 100%;
  overflow: hidden;
}
body { /* can also be whatever container */
  display: flex;
  display: -webkit-flex;
  display: flex;
  -webkit-align-items: center;
  align-items: center;
  -webkit-justify-content: center;
  justify-content: center;
}
#wrapper {
  padding: 30px;
  background: #000;
  color: #fff;
}