This is brilliant! Can't wait for mobile in-game to compliment this. Seems pretty stable, here's a few cosmetic suggestions:
(I'm using BB Q10, default browser)
Might be a good idea to move the big red "Sign up to play!" button closer to the top, and scrap the thin little Welcome / Login / Sign Up nav, and instead just have another big red "Login" button beside the sign up. The nav bar looks kinda squished (at least on my browser)
Not sure if this is just my phone, but the advirtisment at the top is just slightly cut off on the left side with a narrow blank space on the right side.
The "Competitive Setups" section has a red heart beside it instead of a gold heart, which may lead to some confusion.
And here's a couple other ideas regarding the actual mobile lobby function:
I think the "pinned setups" tab on the mobile lobby is a lot more intuitive and easy to work with than the current "Find Setup" and "Create Setup" if a user is looking to start their own game on a mobile device. You might wanna just have a "Create Game" button that brings you to the pinned setups, and instead have the classic find setup and create setup navigate available from there if the user wants something special.
Something to think about if you're going to be investing a lot in the mobile lobby / game is a "quick join" button that the user can configure... here's a sketch of how that might work:
Automatically join closest to full setup in the lobby as long as it passes the user's filters (default to listed featured, favorited, and competitive setups, red or gold heart). If none matching available, create a random setup from the user's filter list, preferring comp setups that are also on the user's favorites list, etc. Default would be red heart if the user hasn't joined the round competition, or gold if they have. Simple filter configuration could just be checkboxes for comp, featured, and favorited setups, with an advanced option where the user can just add setups in a priority list.