JSFiddle - React, Tailwind, and code Playground
HTML
<div>
<ul>
<li>First</li>
<li>Second</li>
<li>Third</li>
</ul>
</div>
JavaScript
$("div li:first-child").css("border","1px solid red");
<div>
<ul>
<li>First</li>
<li>Second</li>
<li>Third</li>
</ul>
</div>
$("div li:first-child").css("border","1px solid red");