Genesis – Custom Post Class
You can set a custom post class to style some posts differently on an archive page. For instance, you may want to style posts in the “Featured” category differently than posts in other categories.
Below is the code which adds a custom post class to posts in the “Featured” category:
// Add custom post class to posts in the "Featured" category
add_filter('post_class', 'wpb_custom_post_class');
function wpb_custom_post_class($classes)
{
$new_class = 'featured-post';
if (in_category('Featured'))
$classes[] = esc_attr(sanitize_html_class($new_class));
return $classes;
}
Please see the Conditional Tags?codex page for more details regarding the functions that can be used to test for various conditions.