JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block">
  <span class="block__text">Hello world</span>
</div>

CSS

.block {
  width: 200px;
  height: 200px;
  background-color: #ccc;

  display: table;
}
.block span {
    display: table-cell;
    vertical-align: middle;
}