JSFiddle - React, Tailwind, and code Playground

by iii l

HTML

<div class='a'><a class='a' href='#'>ссылка</a></div>
<div class='hello'>hello</div>

CSS

* {margin:0;padding:0;}
.a {background:green;height:500px;width:100px;float:left;}
.hello {background:blue;height:500px;width:0;-webkit-transition: width 1s ease-out;-moz-transition: width 1s ease-out;-o-transition: width 1s ease-out;transition: width 1s ease-out;}
.hi {width:400px;}

JavaScript

$('a.a').click(function(){
    $('div.hello').toggleClass('hi');
});