I'm looking to develop a custom look and feel for a Community.  Particularly the kind of look and feel that is often seen on demo sites presented by Salesforce such as the one on this video http://www.youtube.com/watch?v=AoF45TwuzPo at 20:23 - the Cirrrus Demonstration org.  I understand VF and Site.com could be used but I don't know what would be involved in setting up this kind of look and feel (note particularly the tabs, rounded corners, clean layout etc).

Can anybody help please?

I'm looking to develop a custom look and feel for a Community.  Particularly the kind of look and feel that is often seen on demo sites presented by Salesforce such as the one on this video http://www.youtube.com/watch?v=AoF45TwuzPo at 20:23 - the Cirrrus Demonstration org.  I understand VF and Site.com could be used but I don't know what would be involved in setting up this kind of look and feel (note particularly the tabs, rounded corners, clean layout etc).

Can anybody help please?