JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
<div class="child">
d
</div>
</div>

CSS

.parent{
  width:500px;
  height: 500px;
 background-color:red;
 display: flex;
    align-items: center;
}

.child {
  width:300px;
  height: 300px;
 background-color:blue;
}