JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div></div>
    <div class = 'expand'>
        <div id = 'a'></div>
        <div id = 'b'></div>
        <div id = 'c'></div>
        <div id = 'd'></div>
    </div>
 
</body>

CSS

div{
	width: 100px;
	height: 100px;
	background-color: #cc0000;
    
}

.expand{
    width: 300px;
    height: 300px;
    background-color: yellow;
}

#a{
    width: 150px;
    height: 150px;
    background-color: red;
}

JavaScript

$(document).ready(function(){
    $('div').hover(function(){
        $(this).addClass('expand', 'slow');
    });
});