I would like to apply some modification to the look of the them I'm using.
Please, can anybody explain where

1) I can change the color of the menu

2) I can change the header in pages (I would like to insert a bigger jpg logo than the basic 128x128 pixel)

3) no way to group categories in sub-categories ? (I have many different articles and the only idea I had to have no a long menu under categories is to create many shops as the categories I have... No way for better solutions?)

Thanks for any reply :-)

4) Where are located the "id" ?

5) no way to have the footer center aligned ?