JSFiddle - React, Tailwind, and code Playground

HTML

<div id=el></div>

CSS

#el {
    width: 300px;
    margin: 20px auto;
    height: 150px;
    --box-shadow-color: palegoldenrod;
    box-shadow: 0px 0px 7px var(--box-shadow-color);
}
#el:hover {
    --box-shadow-color: goldenrod;
}