JSFiddle - React, Tailwind, and code Playground

HTML

<div id="C">
     <div id="Z">    
         <br><br>
         <div class="X"></div><br><br><br><br><br>
         <div class="X"></div><br><br><br><br><br>
         <div class="X"></div><br><br><br><br><br>
     </div>
</div>

CSS

#C { width: 100%; background-color:black; height: 350px; }

#Z { background-color: blue; }

.X { margin-left: 120px; height: 40px; background-color: white;}