JSFiddle - React, Tailwind, and code Playground

HTML

<div class="test">
<div class="test22">

</div>
</div>

CSS

.test {
  width: 100%;
  height: 100%;
}

.test22 {
  width: 100px;
  background-color: #000;
  border: 1px solid #000;
  height: 100%;
}