Hi all
I think it is pretty obvious that all themes will share quite big load of CSS. Originally I though about extracting these bits to Theme class methods, but now I think it would make things even harder to maintain.
What I feel would be better to create core CSS file, which would be always included and theme authors will just override/extend it.
This way, we can make changes in core without breaking older themes too much - maybe some things will not look 100% intergrated, but at least the layout won't be broken.
Currently original and pmahomme themes share about 2500 lines, they differ in 1000/500 (pmahomme/original) lines.