Styling <amp-accordion>

We can style the header and section of the accordion with CSS. Let's keep it simple with a grey, top border as divider between sections and no background color:

.category-title {
  font-family: Georgia, 'Times New Roman', serif;
  font-size: 1.5rem; 
  color: #005689;
  background: none;
  border:0;
  border-top: 1px solid #ddd;
  padding:0.25rem;
}

This gives us a nice list of top stories expandable by category: