CSS cleanup and prettification.
CSS cleanup and prettification.

The 'one rule per line' style is consistent with the rest of Mezzanine
and makes diffs easier, as well as making the styles more accesible
for newcomers.

traxxas/cartridge,stephenmcd/cartridge,ryneeverett/cartridge,wyzex/cartridge,Kniyl/cartridge,traxxas/cartridge,traxxas/cartridge,syaiful6/cartridge,Kniyl/cartridge,syaiful6/cartridge,syaiful6/cartridge,dsanders11/cartridge,dsanders11/cartridge,dsanders11/cartridge,Parisson/cartridge,wbtuomela/cartridge,Parisson/cartridge,stephenmcd/cartridge,Parisson/cartridge,wyzex/cartridge,wbtuomela/cartridge,stephenmcd/cartridge,wbtuomela/cartridge,Kniyl/cartridge,wyzex/cartridge,jaywink/cartridge-reservable,jaywink/cartridge-reservable,ryneeverett/cartridge,ryneeverett/cartridge,jaywink/cartridge-reservable