How can I change the page width of the style?
Go to Style Properties -> Page setup -> Maximum page width
How do I set my own logo?
Go to Style Properties -> Basic Options, you can upload your logo here.
How can I change the blue header?
Go to Style Properties -> Header and navigation -> Header/logo row, the gradient is set in the Extra box.
How can I change the blue footer?
Go to Style Properties -> Footer -> Footer, the gradient is set in the Extra box.