<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<section class="main-content py-5 mb-5" id="main-content">
<div class="container">
<div class="row">
<div class="col-md-8 ">
<div class="card-body bg-light border">
column8
</div>
</div>
<div class="col-md-4 ">
<div class="card bg-light">
<div class="card-body">
column4
</div>
</div>
</div>
</div>
</div>
</section>
