JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <div>one</div>
    <div>two</div>
    <div>three</div>
    <div>four</div>
    <div>five</div>
    <div>six</div>
    <div>seven</div>
    <div>eight</div>
    <div>nine</div>
    <div>ten</div>
    <div>eleven</div>
</div>

CSS

div:nth-child( 3n + 2 ) { background-color: green }