JSFiddle - React, Tailwind, and code Playground

HTML

<div class="blue">Hello</div>

CSS

.box {          
width: 250px;
height: 100px;    
border: 1px #000 solid;
}

.red {
background: red;
}

.blue {
background: blue;
}

JavaScript

$('div').click(function() {
    $(this).toggleClass('red blue');
});