JSFiddle - React, Tailwind, and code Playground

HTML

<div id="parent">
    <div id="child">
    </div>
</div>

CSS

#parent{
  width: 100px;
  height: 100px;
  border: 1px solid red;
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

#child{
  width: 20px;
  height: 20px;
  border: 1px solid blue;
}