JSFiddle - React, Tailwind, and code Playground

by Curry

HTML

<p id="aap">OHAI!</p>

CSS

p {
    opacity:1;
    transition:opacity 500ms;
}
p.waa {
    opacity:0;
}

JavaScript

setTimeout(function(){
    document.getElementById('aap').className = 'waa';
}, 2500);