Design feedback from Roman

[ebidel]

• [x] Navigating from Attend Offsite to Videos should quickly transition tab text to white, otherwise there's a long moment where text is illegible
• [x] The tabs in the surface coming from the FAB on the homepage should have cursor:pointer

@devnook where's the best place to deal with 1?

[ebidel]

1 is addressed in https://github.com/GoogleChrome/ioweb2015/commit/931a0d000f8a7cfb3a2d036d5d05263db2af64b7