how to change select box colors

[Guest_imported]

Hi, I've already created a style sheet so my background color in my slect box is black and my font color = white.
This is what I have at the moment

http://www.nitrostest.f2s.com/woordenboek.html

As you can see I still have a white border around my box : How do I change that into a black border ? I aso would like to change the color of de dropdown button itslef, is this possible and how do I have to do it ,