JSFiddle - React, Tailwind, and code Playground

HTML

<div id="red"></div>
<div id="gray"></div>

CSS

#red {
  width: 100px;
  height: 100px;
  background: red;
}

#gray {
  width: 100px;
  height: 100px;
  background: gray;
  margin-top: 10px;
}