JSFiddle - React, Tailwind, and code Playground

by Felis Catus

HTML

<div class=container>
<div class=containee>ю
</div>
</div>

CSS

.container{
    position: absolute;
    top: 1px;
    left: 1px;
    width: 100px;
    height: 100px;
    box-shadow: 0 0 1px red;
}
.containee {
    width: 50px;
    height: 50px;
    margin: 50% 0 0 50%;
    box-shadow: 0 0 1px blue inset;
}

JavaScript

(function(){
  setTimeout(function(){
    document.querySelector('.container').style.width='300px';
  }, 2000);
})();