JSFiddle - React, Tailwind, and code Playground

HTML

<div align="right" id="myMenu">
    <ul>
        <li><a href="#" data-id="appstructurediv">Structure</a>
        </li>
        <li id="style"><a href="#" data-id="appstylediv">Style</a>
        </li>
        <li><a href="#" data-id="appdetailsdiv">Details</a>
        </li>
    </ul>

CSS

#myMenu ul li {
    display: inline;
}

#myMenu ul li a {
    background-color:#333333;
    text-transform: uppercase;
    font-weight: bold;
    font-family:"Open Sans", Arial, sans-serif;
    font-size:12px;
    text-decoration: none;
    padding: 1em 2em;
    color: #000000;
    border-left:1px solid #333333;
    border-right:1px solid #333333;
    border-top:1px solid #333333;
}
#myMenu ul li a:hover {
    color: #fff;
    background-color: #999999;
}

#myMenu ul li a.selection {
    background-color: #000000;
    border-bottom:10px solid #000000;
    border-top:9px solid #000000;
}

JavaScript

$(function () {
     $("li:first-child").addClass("selection");
     $('li').click(function () {
         $('#myMenu li a').removeClass('selection');
         $(this).find('a').addClass('selection');
     });
 });