penders - 5:11 pm on Dec 12, 2011 (gmt 0)
IMO I would have said they would all be part of your color.css. (topography = typography ?) text-shadow could be part of typography.css, but that's debatable.
However, I'd question whether it was a good idea to split your main CSS file into three? Three files means 3 HTTP requests which potentially slows things down. You could perhaps have 3 separate sections in the 1 CSS file? Or, if you wanted to have 3 physical files, combine these server-side and send a single combined file to the client?
But I think I'd only split the CSS up like this if I wanted to give separate control to another process. eg. the end user might want to change the colors. But I don't think this is always relevant? Just my opinion.