JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Click anywhere</h1>

<div class="me">
    Hi stackoverflow!
</div>

CSS

.me {
  opacity: 0.0;
  background-color: aqua;
  width: 200px;
  height: 50px; 
  transition: all 5.3s linear;
}

.me.happy {
  opacity: 1.0;
}

JavaScript

$(document).ready(function() {
    $(this).click(function() {
        $('.me').addClass('happy');
    }); 
});