Make comments look different from Node text

At the moment (if this is still current) comments look just the same as the main node text. http://www.kiwi-themes.com/demosite-1/node/43

They are just recognizable by the parting line and a header that sais comments.

From a Information-Architecture Standpoint, comments must be clearly visible as such, else they can be mistaken as belonging to the main text. This might even drive the owner of a blog into serious legal trouble... (this is if they don't moderate their comments ;) )