JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>one</li>
    <li>two</li>
    <li class='active'>three</li>
    <li>four</li>
    <li>five</li>
    <li>six</li>
</ul>

CSS

/* before .active */

/* after .active */
ul li.active+ li{
  background:blue;
}

JavaScript

$(document).ready(function() {
	$(".active").prev("li").css("background", "red");
})