JSFiddle - React, Tailwind, and code Playground

HTML

<div id="countdownBoxContainer2">
<div id="countdownBox">
   lala</div>
  </div>


<div id="countdownBoxContainer">
    <div id="countdownBox">
        <div>hi there</div>
    </div>
 </div>
  
  
  
  <div id="countdownBoxContainer2">
  <div id="countdownBox">
       lala
       </div></div>

CSS

html,
body {
    height: 100%;
}

#countdownBoxContainer {
    display: table;
    height: 80%;
    width: 100%;
}

#countdownBox {
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}
#countdownBoxContainer2 {
    display: table;
    height: 10%;
    width: 100%;
}

#countdownBox2 {
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}