A collection (or any umber of them) is referenced in both collections:
- Default tablet
- Default phone
Each default collection has a separate set of Grid and Card Layouts assigned and each looks good in their respective target device class.
Each of those collections that are referenced in both default collections, can only have one Grid and Card Layout assigned to their respective browse pages. I say we should be able to attach two Grid and Card Layouts to those collections. That way we can make sure the browse pages for these collection look the best they can in each device class. Or, better yet: Stock Responsive Layouts?
We're working on adding support for this right now. At the moment, all you can do is create two different collections (one for phone and one for tablet) and then apply the two different layouts to each.
Edit: To clarify, I mean we're working on adding the ability to specify a phone layout and tablet layout on a collection at the same time.