JSFiddle - React, Tailwind, and code Playground

HTML

<ul><li>1</li><li>2</li><li>3</li></ul>

CSS

ul li {
    display:block;
    background-color: #ccc;
    padding 5px;
    margin: 5px;
}
Ul li:hover {
    background-color: #000;
    color: #fff;
    transition: ease-out 0.5s;
}