JSFiddle - React, Tailwind, and code Playground

HTML

<div class="div-shadow"></div>

CSS

.div-shadow {
    display: block;
    height: 400px;
    width: 400px;
    background-color: #CCC;
    margin: 20px auto;
}

.div-shadow:hover {
    -moz-box-shadow: 0 0 20px #08C;
    -webkit-box-shadow: 0 0 20px #08C;            
    box-shadow: 0 0 20px #08C;
}