JSFiddle - React, Tailwind, and code Playground

HTML

<div> </div>
<div> </div>
<div> </div>
<div> </div>
<br>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<br>
<div> </div>
<div> </div>
<div> </div>
<div> </div>

CSS

div {height: 20px;margin: 5px;}
div:nth-child(1n) {background: blue;}
div:nth-child(2n) {background: red;}
div:nth-child(3n) {background: green;}
div:nth-child(4n) {background: black;}