JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">
    <ul>
        <li><a href="#">test 1</a>

        </li>
        <li><a href="#">test 2</a>

        </li>
    </ul>
</div>

CSS

ul {
    list-style: none;
    margin: 0;
    border-bottom: 5px solid green;
    position:relative;
    padding:0;
}
ul li {
    padding:10px 10px;
    margin-left: 20px;
    display:inline-block;
    position:relative;
    bottom:-5px;
    border-bottom: 5px solid transparent;
}
a {
    text-decoration: none;
    display: block;
}
li:hover {
    border-color:red;
}