Adding conditional css to view or display type
You could try this but may depend on your 'favourite' field output

If you click on "Format > settings" when editing your view you'll see a "Row class" field. In there you can put the replacement pattern for your favourite field. 

So if its populated it will add the field value as a class to the view-row div. And you can use this to know if the field has content

If that's not going to work because the field content isn't suitable as a class then you could preprocess the node view and add a class yourself in the attributes array