1) Demosite contains custom blue colored markup which isn't affected by skin fully. Please open any component page in order to see how the skin affects the components. All the demo was not skinned because the standard elements skinability and themes mechanisms was not implemented when it was under development :)
2) Yes skinability could be used not only for the components itself but also for standard elements. correspoding demo page(standard skinning) shows the examples.
Ahkay. Makes sense. Just not what I expected, obviously. :)
I'll take a better look.