Well you're a coder NOW man!
I just took a look in a css file to see what's in there just because I never really have. Using internalz pro, I navigated to /usr/palm/applications and looked inside com. palm.app.email
I opened the stylesheets folder and saw several CSS files so I just opened each and looked for #FFFFs or anything similar.
I saw things like this:
So the next thing I would try, is plugging the device into a PC, navigating to the folder for agendaZ, and opening all of its CSS files individually with notepad, then use its Find function and search for the word "color". Will windows explorer browse to those files? Do you need to associate the CSS file extension to open with notepad? Idk.
Since you are trying to change some color you don't like, if that color isn't black or white, you can ignore any instances where you see those values. You are looking for the value of whatever color it is you want to replace. Idk what that color is, but if you had the value, you could search for it specifically.
You could also use a known color value as a" tracer," like whatever is the value for hot pink, and sub it in, then open app and see what changed.