JSFiddle - React, Tailwind, and code Playground

HTML

<div class="nav">
    <ul>
        <li class="selectedPage"><a href="#">HOME</a></li>
        <li><a href="#">PAGE1</a></li>
        <li><a href="#">PAGE2</a></li>
    </ul>
<!-- end .nav --></div>

CSS

ul, li {
    padding: 0;  
    margin: 0;
}

div.nav {
    width: 750px;
    background: #52b5f0; /* Old browsers */
    /* IE9 SVG, needs conditional override of 'filter' to 'none' */
    background: url(data:image/svg+xml;base64,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);
    background: -moz-linear-gradient(top,  #52b5f0 5%, #3699d0 49%, #19638a 95%); /* FF3.6+ */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(5%,#52b5f0), color-stop(49%,#3699d0), color-stop(95%,#19638a)); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  #52b5f0 5%,#3699d0 49%,#19638a 95%); /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  #52b5f0 5%,#3699d0 49%,#19638a 95%); /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  #52b5f0 5%,#3699d0 49%,#19638a 95%); /* IE10+ */
    background: linear-gradient(to bottom,  #52b5f0 5%,#3699d0 49%,#19638a 95%); /* W3C */
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#52b5f0', endColorstr='#19638a',GradientType=0 ); /* IE6-8 */
}

div.nav ul {
    list-style: none; /* this removes the list marker */
    overflow: hidden;
}

div.nav li {
    float: left;
  /*display: inline-block;*/
}

div.nav li.selectedPage {
    background: #41ff5f;
}

div.nav li.selectedPage a {
    color:...