It's good to see consistency between the sites. One thing I noticed is that when accessing the support or knowledgebase sites from inside the billing portal, you get both headers--the new header is within the billing header. Accessing these pages also changes the color scheme (slightly) in the billing tabs--the font on the tabs becomes black.

Do you intend to import this header to the billing portal? If so, can you have it 'skip' the header when accessing the support/knowledgebase pages from the billing system?