JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="main-ul">
   <li><a href="#">About MHG</a></li>
    <li><a href="#">Workout Programs</a></li>
    <li><a href="#">Fitness Tips</a></li>
    <li><a href="#">Contact Us</a></li>          
    <li><a href="#">Read Our Blog</a></li>
</ul

CSS

li{list-style:none;}
.selected{background:red;}
.selected a{color:#fff;}

JavaScript

$(document).ready(function(){
    $("#main-ul li").click(function(){
        $('li').removeClass("selected");
        $(this).addClass("selected");
    })
})