JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <span>I'm vertically/horizontally centered!</span>
</div>

CSS

.container {
    position: absolute;
    top: 50%;
    left: 50%;
    -moz-transform: translateX(-50%) translateY(-50%);
    -webkit-transform: translateX(-50%) translateY(-50%);
    transform: translateX(-50%) translateY(-50%);
}