JSFiddle - React, Tailwind, and code Playground

HTML

<div class="progress-bar">
    <div class="progress">hover</div>
</div>

CSS

*{
    margin: 0;
    padding: 0;
}

.progress-bar{
    margin: 10px;
    width: 100px;
    height: 20px;
    background: red;
}

.progress{
    -webkit-transition: width .5s ease;
    -moz-transition: width .5s ease;
    -ms-transition: width .5s ease;
    -o-transition: width .5s ease;
    width: 70px;
    height: 17px;
    font-family: Arial;
    font-size: 10px;
    color: #000;
    overflow: hidden;
    padding: 3px 5px 0 5px;
    background: #CCC;
}

.progress-bar:hover{
    cursor: default;
}

.progress-bar:hover .progress{
    width: 40px;
}