JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div class="nothing">
    </div>
    <div class="child">child 1 <!-- SELECT THIS ONE -->
    </div>
    <div class="child">child 2 <!-- NOT THIS ONE -->
    </div>
    <div class="child">child 3 <!-- NOT THIS ONE -->
    </div>
</div>

CSS

.child:nth-child(2) { color:red; }