JSFiddle - React, Tailwind, and code Playground

HTML

<div class="catdiv">
    Hey, I'm a cat div
</div>

CSS

.catdiv,
.catdiv:hover {
    transition: background-color 500ms;
    -webkit-transition: background-color 500ms;
    -moz-transition: background-color 500ms;
    -ms-transition: background-color 500ms;
    -o-transition: background-color 500ms;
    background-color: #161616
}
.catdiv {
    background-color: #FFD800;
}
}