JSFiddle - React, Tailwind, and code Playground

HTML

<div style="box-shadow: 1px 1px 4px rgba(0, 0, 0, 0.08), 1px 1px 4px rgba(255, 255, 255, 0.08) inset;border: 1px solid #DDD;
background-color: #FFF;
text-align: center;
border-radius: 10px;
width:100%;
height:50px; position:relative;

">
    <ul class="dropdown">
        <li>Section1
            <ul>
                <li>Link</li>
                <li>Link</li>
                <li>Link</li>
                <li>Link</li>
                <li>Link</li>
            </ul>
        </li>
    </ul>
</div>

CSS

<style> body {
    font-family:'Lucida Grande', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    padding: 20px 50px 150px;
    font-size: 13px;
    text-align: center;
}
.dropdown {
    text-align: left;
    display: inline-block;
    margin: 0;
    padding: 0px 4px 0px 0px;
    list-style: none;
    position:absolute;
    top:0;
}
.dropdown li {
    font: bold 12px/18px sans-serif;
    display: inline-block;
    margin-right: -4px;
    /*padding: 15px 20px;*/
    background: #fff;
    cursor: pointer;
    -webkit-transition: all 0.2s;
    -moz-transition: all 0.2s;
    -ms-transition: all 0.2s;
    -o-transition: all 0.2s;
    transition: all 0.2s;
}
.dropdown li:hover {
    background: #555;
    color: #fff;
}
.dropdown li ul {
    padding: 0;
    position: absolute;
    top: 18px;
    left: 0;
    width: 150px;
    -webkit-box-shadow: none;
    -moz-box-shadow: none;
    box-shadow: none;
    display: none;
    opacity: 0;
    visibility: hidden;
    -webkit-transiton: opacity 0.2s;
    -moz-transition: opacity 0.2s;
    -ms-transition: opacity 0.2s;
    -o-transition: opacity 0.2s;
    -transition: opacity 0.2s;
}
.dropdown li ul li {
    display: block;
    color: #000;
    padding-bottom: 5px;
}
.dropdown li ul li:hover {
    background: #666;
}
.dropdown li:hover ul {
    display: block;
    opacity: 1;
    visibility: visible;
}
</style>