Add comments to screen.css.
Add comments to screen.css.

gaapt/bookyt,wtag/bookyt,huerlisi/bookyt,xuewenfei/bookyt,hauledev/bookyt,wtag/bookyt,silvermind/bookyt,huerlisi/bookyt,silvermind/bookyt,xuewenfei/bookyt,silvermind/bookyt,hauledev/bookyt,gaapt/bookyt,silvermind/bookyt,hauledev/bookyt,hauledev/bookyt,wtag/bookyt,gaapt/bookyt,huerlisi/bookyt,xuewenfei/bookyt,gaapt/bookyt