Create Bootstrap Wells

Bootstrap has a class called well that can create a visual sense of depth for your columns.

Nest one div element with the class well within each of your col-xs-6 div elements.

<div class="container-fluid">
  <h3 class="text-primary text-center">jQuery Playground</h3>
  <div class="row">
    <div class="col-xs-6">
      <div class="well">



      </div>
    </div>
    <div class="col-xs-6">
      <div class="well">



      </div>
    </div>
  </div>
</div>