JSFiddle - React, Tailwind, and code Playground

HTML

<div class="red" onclick="alert('red');"></div>
<div class="blue" onclick="alert('blue');"></div>

CSS

div {
    display:inline-block;
    width:100px;
    height:100px;
}
div.red {
    background-color:red;
    opacity:1;
}
div.blue {
    background-color:blue;
    opacity:0.0001;
}