markup.html

<aside>
   <div class="widget">
       <h5 class="widget-title">
       <p></p>
   </div>
   <!-- other widgets -->
</aside>

<!-- CSS:

  aside { background-color: #ccc; }
  aside .widget { background-color: white; padding: 10px; }
  aside .widget h5 { border-bottom: 1px solid black; }

-->

<section>
  New section goes here
</section>

<!-- CSS:
  section { margin: 20px; border: 1px solid blue; }
-->