Basic questions. Or not.

Maybe what I’m asking here is basic, but really need help in this:. And sorry to be so many things, but I decided to ask all at once:

1 – How to put a different color on the bottom of each widget?

2 – How to put a background color in the title of each widget sidebar, like a stripe full width of the sidebar?

I think that’s, at least for now. Thank you!