CSS for <SELECT>

In a form I have placed a <select> item, and some <input type="text"> items.

All the items have a CSS style, wich gives a specific color to background, border, text, etc.

Only the Select-items still have the default border, not the border that's defined in the CSS. Can someone explain me how I change these borders?

Also, there is this arrow-button in such a select-item, wich opens all the available options. With CSS I'd like to change the colors of this button too.. but I don't know how to do that..