How to change UI headers and button color in addon 1.0

Hello Gurus

We are trying to implemnt ADDON 1.0 in SRM.

One of our client's request is to change the UI look  a bit.

For example:

How can we change button color from yellow (when it's the next step in sc) to other color.

How do we change fields header color or add an asterik next to the field header (for ourpose of indicating that the field should be filled with data).

Thanks a lot

Jenifer