JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <div class="red">Lorem ipsum dolor sit amet, consectetur adipisicing elit. In quod nihil .</div>
  <div class="green">necessitatibus quam doloribus eos harum delectus, aspernatur accusantium, </div>
</div>
<button id="small">
click
</button>

CSS

#container { max-width:70%; height:500px;border:2px dotted maroon; }
.red, .blue, .green { display:inline-block;max-width: 50%; height:auto; margin:0 auto;}
.red {background:red; opacity:0.9; float:left; }
.green { background:green;  opacity:0.9; float:right; }

JavaScript

$('#small').click(function() {
  $('#container').animate({
    'width': '200px'
  }, 5000, function() {})
})