JSFiddle - React, Tailwind, and code Playground

HTML

<div class="slider">
    MY TEXT CONTENT
    <div class="hide">OOOOOOOOOOOOOW</div>
</div>

CSS

.slider {
    padding: 15px;
    margin: 25px;
    background-color: #eee;
    border: 1px solid #ccc;
    border-radius: 7px;
    cursor: default;
}

.hide {
    overflow: hidden;
    height: 0;
    transition: height .25s;
    background-color: white;
    border-radius: 4px;
}

.slider:hover .hide {
    height: 22px;
}