JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <ul>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
        <li data-item>Item</li>
    </ul>
</div>

CSS

.container {
    border: 1px solid #ccc;
    font-family: sans-serif;
    height: 400px;
    overflow: hidden;
    position: relative;
    width: 200px;
}

.container:after {
    background: linear-gradient(to bottom, rgba(255, 255, 255, .3) 0%, white 100%);
    bottom: 0;
    content: " ";
    height: 150px;
    display: block;
    position: absolute;
    width: 100%;
    pointer-events: none;
}

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
}

li {
    cursor: pointer;
    margin: 3px;
    padding: 3px;
    text-align: center;
}

li:hover {
   background: #99d; 
}