Change Master Page CSS Dynamically in SharePoint 2010

Question

I wanna know that how can we have different header color for different site collections like if I have created a site collection for ID 9080 having URL as (/usmanpc/9082/) and have top color assigned for it as blue, same i have another site collection for ID 9081 having URL as (/usmanpc/9081/) and have assigned green color for it's top header means that title bar. The problem is that I have created these two site collections via programming in c# and but how can I assigned or fixed the above 2 different colors for both those 2 different site collections. Any suggestions would be appreciated. Please bring me out of this nasty situation.

Answer 1

I could think of custom solution with included different masterpages for the different site collections with the desired custon css. Depending on how the custom solution is organized I would recommend activating the custom feature or just changing the masterpage of the site
through automated powershell scripts (if you need to update many subsites for example)