JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li><a class="a" href="#">Nenu item 1</a></li>
    <li><a class="b" href="#">Nenu item 2</a></li>
    <li><a class="c" href="#">Nenu item 3</a></li>
    <li><a class="d" href="#">Nenu item 4</a></li>
    <li><a class="e" href="#">Nenu item 5</a></li>
</ul>

CSS

body {
    font-family: Arial, Helvetica, sans-serif;
    font-size: 16px;
    line-height: 1.45;
}

ul {
    width: 200px;
    background: #111;
    margin: 0;
    padding: 20px;
    list-style: none;
    text-align: center;
}

li {
    margin: 10px 0;
}

a {
    color: #eee;
    text-decoration: none;
    display: block;
    position: relative;
    padding: 5px 0;
    overflow: hidden;
    
}

a:after {
    content: '';
    position: absolute;
    width: 90%;
    height: 1px;
    bottom: 0;
    left: 50%;
    margin-left: -45%;
    background: linear-gradient(to right, rgba(238,238,238,0) 0%,rgba(238,238,238,1) 35%,rgba(238,238,238,1) 65%,rgba(238,238,238,0) 100%); /* W3C */
}

.a:after {
    width: 0;
    margin-left: 0;
}

.a:hover:after {
    width: 90%;
    margin-left: -45%;
    -webkit-transition: 0.5s;
    transition: 0.5s;    
}

.b:after {
     opacity: 0;   
}

.b:hover:after {
    opacity: 1;
    -webkit-transition: 0.5s;
    transition: 0.5s;    
}

.c:after {
     left: -100%;
    margin-left: 0;
}

.c:hover:after {
    left: 50%;
    margin-left: -45%;
    -webkit-transition: 0.5s;
    transition: 0.5s;    
}

.d:after {
    left: auto;
    right: -100%;
    margin-left: 0;
}

.d:hover:after {
    right: 50%;
    margin-right: -45%;
    -webkit-transition: 0.5s;
    transition: 0.5s;
}

.e:after {
    bottom: 200%;
}

.e:hover:after {
    bottom: 0;
    -webkit-transition: 0.5s;
    transition: 0.5s;    
}