JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#">show</a>

<div></div>

CSS

div {
    display: none;
    opacity: 0;
    width: 100px;
    height: 100px;
    background: #366D93;
    -webkit-transition: opacity 7s ease-in-out;
       -moz-transition: opacity 10s ease-in-out;
        -ms-transition: opacity 10s ease-in-out;
         -o-transition: opacity 10s ease-in-out;
            transition: opacity 10s ease-in-out;
}

JavaScript

$('a').click(function(){
        $('div').show().animate({'opacity':1});
    });