@botsmack... yes, I'm having the exact same problem :( This is an amazing custom css style, but unfortunately, Google broke it after they modified the interface a month or so ago (during SXSW, I think) to give us about 17 extra pixels. Thanks google, but you made it worse for me ;).
I've gone back to using Google reader sans this custom style, but check back here every week hoping that Mr. Hicks has updated.
Jon - If you're reading this... please help a bruvva out. Your custom style makes me want to lick me screen.
About OS X Style Google Reader on Apr 07 2008