The classes have to be defined per container file and often we use an 'id' selector to separate things that are similar but may have different colours.
A quick fix would be to have something like this -
In a blue container file - you would use a class identifier for the title to be blue_title - and in the css file - define the blue title details there.
In the white container file - you would have a class identifier for the title to be white_title - and in the css file define the colour there.
For me, it's not that I'm lazy - I just look for efficiency- so, I do generally two sets of classes in all my files that have contrasts that require either white / light or black/dark text.. So I have boring and generic - lightBG and darkBG classes assigned to alot of my skin files and if you follow this method and get all the links nicely formatted, the font sizes right, you just use from file to file. So you don't have to think much - you just know whether it's going to use a lightBG class or a darkBG class.
If you are using ascx you add the class parameters into the actual code, if you are using html and xml - you need to assign this in your xml code as well.
So the long and short of it all.. (Or perhaps I should say the light and dark of it all) is you need to assign a different class file for each 'skinobject' in different files so it doesn't take on the class of the first container you add to a page which is an all too common occurance until people get the hang of it.
Nina Meiers