JSFiddle - React, Tailwind, and code Playground
HTML
<ul id="menu">
<li><a href="#"><span>Home</span></a></li>
<li><a href="/_display/"><span>contact us</span></a></li>
</ul>
CSS
.test {background-color:Red;}
JavaScript
$(function () {
$('ul#menu>li: last-child').css(color:'green');
});