JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box">
    <div id="wiki_bar" class="in"></div>
    <div id="vita" class="out"></div>
</div>

<button id="btn-switch" class="punch">The Buttton!</button>

CSS

#box {
    position: relative;
    /*define the you want*/
    height: 60px;
}

#wiki_bar {
    position: absolute;
    height: 100%; width: 100%;
    background: indianred;
    -webkit-transition: 0.3s;
}

    #wiki_bar.in {
        /*waits 1 sec after #vita's 
        transition has finished*/
        -webkit-transition-delay: 0.5s;
    }
    
    #wiki_bar.out {
        -webkit-transition-delay: 0;
        bottom: 100%;  
    }

#vita {
    position: absolute;
    height: 100%; width: 100%;
    background: gold;
    -webkit-transition: 0.4s;
}

    #vita.in {
        /*waits 1 sec after #wiki_bar's
        transition has finished*/
        -webkit-transition-delay: 0.4s;
    }
    
    #vita.out {
        -webkit-transition-delay: 0s;
        visibility: hidden;
        opacity: 0; 
    }



/***************************************************
 * BUTTON BY CHAD MAZZOLA @ http://hellohappy.org/ *
***************************************************/


body {
    /*just so button is centered*/
    text-align: center
}

.punch {
  margin-top: 100px;
  background: #4162a8;
  border-top: 1px solid #38538c;
  border-right: 1px solid #1f2d4d;
  border-bottom: 1px solid #151e33;
  border-left: 1px solid #1f2d4d;
  -webkit-border-radius: 4px;
  -moz-border-radius: 4px;
  border-radius: 4px;
  -webkit-box-shadow: inset 0 1px 10px 1px #5c8bee, 0px 1px 0 #1d2c4d, 0 6px 0px #1f3053, 0 8px 4px 1px #111111;
  -moz-box-shadow: inset 0 1px 10px 1px #5c8bee, 0px 1px 0 #1d2c4d, 0 6px 0px #1f3053, 0 8px 4px 1px #111111;
  box-shadow: inset 0 1px 10px 1px #5c8bee, 0px 1px 0 #1d2c4d, 0 6px 0px #1f3053, 0 8px 4px 1px #111111;
  color: #fff;
  font: bold 20px/1 "helvetica neue", helvetica, arial, sans-serif;
  margin-bottom: 10px;
  padding: 10px 0 12px 0;
  text-shadow: 0px -1px 1px #1e2d4d;
  width: 150px;
  -webkit-background-clip: padding-box;
  cursor: pointer;
}

      .punch:hover {
        -webkit-box-shadow: inset 0 0px 20px 1px #87adff, 0px 1px 0 #1d2c4d, 0 6px 0px #1f3053,...

JavaScript

var wiki = document.getElementById('wiki_bar'),
    vita = document.getElementById('vita'),
    btn_switch = document.getElementById('btn-switch'),
    count = 0;

function doSwitch() {
    if( count % 200 === 0 ) {
        vita.setAttribute('class','in');
        wiki.setAttribute('class', 'out');
    } else {
        vita.setAttribute('class', 'out');
        wiki.setAttribute('class', 'in');
    }
    ++count;
}

btn_switch.onclick = doSwitch;