Possible to customise display of Featured Posts in Summary Block?

Site URL: https://maroon-rose-yk6a.squarespace.com/dans-gear

Hello, I am developing a new site for our photos. On the page above, in the top summary block, I would like to apply custom styles only to the "Featured Posts" blog posts.  This summary block has 3 Featured Posts, the others do not have the post flagged as a Featured Posts.  I've attached an example of how I would like a visual indication that these elements are different than the others.  Is this possible in the Custom CSS editor, and if so, what is the class I would use for that? 

The attached image is only an example, and any class that would allow me to customise the style just for those posts (font, font-weight, color etc) would be ok too.

Thanks for any help you can give,

Ann

Thanks very much for this, it's exactly what I need.