I want to take an existing theme and customise the appearance of the unity panel to the way it appears in another theme. I can't find any documentation about how to modify the panel themes, and I've tried comparing several gtkrc files for different themes that have custom panels, moving around bits of text, but I can't figure out how it's done. Basically, I'm trying to put a dark panel with a gradient in the Orta theme.
Where do I find the answer?