 <template is="dom-repeat" items="[[articles]]" as="category">
              <section class="category-page" name="[[category.name]]">
                <!-- 2-columns grid -->
                <two-columns-grid column-width="396" gutter="4">
                  <template is="dom-repeat" items="[[category.items]]" as="article">
                    <article-headline href="#/[[category.name]]/detail/[[article.id]]"
                        article="[[article]]"></article-headline>
                  </template>
     