<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div class="container"> <div class="row"> <h2>Create your snippet's HTML, CSS and Javascript in the editor tabs</h2> </div> <div class="container-fluid"> <h1>Two Unequal Responsive Columns</h1> <p>Resize the browser window to see the effect.</p> <p>The columns will automatically stack on top of each other when the screen is less than 576px wide.</p> <div class="row"> <div class="col-sm-4" style="background-color:lavender;">.col-sm-4</div> <div class="col-sm-8" style="background-color:lavenderblush;">.col-sm-8</div> </div> </div> </div>