Changing the Default Textfield Colour

Hi,

I'm using version 6.34.

My site's colour scheme is white text on a black background.  Unfortunately this means that, as testfields have white backgrounds, white text cannot be seen in any post unless the user choosers to change the default colour.

So I'm wondering....is there:

a) a way to ensure that the default text colour inside textfields is black, whilst normal text remains white?

or:

b) a way to change the backgound colour of all textfields from white to black, so that white text will be visible?

Thanks

Ben