JSFiddle - React, Tailwind, and code Playground

HTML

<div id="a"><div id="b"></div></div>

CSS

#a {
  border:1px solid blue;
}


#b {
  display: inline-flex;
  border:1px solid red;
  width:50px;
  height:50px;
}


#b:after {
  display:table;
  content:'';
}