drop down menus problem!

[digz]

I have attached a couple of screen grabs of the problem - when the drop down is not selected it has a white background and white text - but if you look at the selected screen grab you will see that all of the list goes is black background with white text!!!

Where do I fix this and get some consistency! - preferably always a black backround?

The same problem is happening with the text field and submit buttons - if you look at pic 3&4 you will see what I mean - is there a specific line in the css that is causing it? or is there any css that will allow me to overwrite all the other css and make the form elements look exactly as I want them?