Make app-bar styles more specific
Make app-bar styles more specific

This makes the selectors for app-bar styles a lot more specific to get
around some errors we were seeing in Firefox.  In Firefox, we were
seeing styles from other elements jump scope and apply to the app-bar,
so we now make sure that will not happen.

Fixes #1845

MinFu/uproxy,jpevarnek/uproxy,roceys/uproxy,chinarustin/uproxy,roceys/uproxy,dhkong88/uproxy,chinarustin/uproxy,uProxy/uproxy,roceys/uproxy,jpevarnek/uproxy,dhkong88/uproxy,qida/uproxy,dhkong88/uproxy,uProxy/uproxy,qida/uproxy,dhkong88/uproxy,jpevarnek/uproxy,qida/uproxy,qida/uproxy,qida/uproxy,chinarustin/uproxy,roceys/uproxy,chinarustin/uproxy,dhkong88/uproxy,MinFu/uproxy,uProxy/uproxy,roceys/uproxy,jpevarnek/uproxy,chinarustin/uproxy,uProxy/uproxy,MinFu/uproxy,jpevarnek/uproxy,uProxy/uproxy,MinFu/uproxy,MinFu/uproxy