JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

ul {
    display: block;
    width: 40px;
    padding-top: 20px;
}
li {
    display: block;
    width: 30px;
    height: 60px;
    background-color: #303030;
    border: 1px solid #FFFFFF;
    border-radius: 0 20px 0 0;
    margin-top: -20px;
    background: -webkit-linear-gradient(top, rgba(0,0,0,0) 5%,rgba(0,0,0,1) 50%);
   
}
li:last-child {
    height: 40px;
}