designbox styles

hi there
i got dolphin 6.0 and currently i'm working on my template. i'd like to have 2 different styles for the left (first_column) and the right (second_column) designbox. does anyone now if there is a way to do that without changing the dolphin core files? not that i wouldn't know how to do that ;-) just i'd like to do the changes in my template only without touching dolphin itself.

cheers