news preset: add box-shadow to article card
news preset: add box-shadow to article card

Add a box-shadow to the article card so it can visually
match the design spec.

https://phabricator.endlessm.com/T10998

endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib,endlessm/eos-knowledge-lib