JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
  <div class="sub">sub content</div>
</div>

CSS

.parent{
  position: relative;
  border: 1px solid;
  
  height:400px;
}
.sub {
  position: absolute;
  height: 100px;
  width: 50%;
  border: 1px solid red;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto;
  text-align: center;
  line-height: 100px;
}