JSFiddle - React, Tailwind, and code Playground

HTML

<div id="outer"></div>
<div id="inner"></div>

CSS

#outer {
    z-index: 2;
    width: 100px;
    height: 100px;
    position: absolute;
    top: 0;
    left: -50px;
    background-color: red;
}

#inner {
    background-color: blue;
    position: absolute;
    z-index: 1;
    top: 10px;
    height: 80px;
    width: 80px;
    left: -80px;
  transition:left .5s;
  -moz-transition:;left .5s;
  -webkit-transition:left .5s;
}

JavaScript

var under = true;
$("#outer").bind({
    click : function() {
        if(under){
          $("#inner").css({
            left: 50,
          });
        }
        else{
          $("#inner").css({
            left: -50,
          });
        }
        under = !under;
    }
});