JSFiddle - React, Tailwind, and code Playground
HTML
<div id="bla"></div>
<h2>Hello</h2>
CSS
#bla {
width:400px;
height:400px;
background-color:green;
opacity: 0;
position: absolute;
}
#bla:hover{
background-color:red
}
JavaScript
setTimeout(function() {
document.getElementById('bla').style.opacity="1";
document.getElementById('bla').style.position="relative";
},2000)