how can i change how URL links in the forums will look like - but only in the forums? (I'd like the links to be of different color compared to the rest of the text)

I already tried this in style.css:
Quote:

but the effect is that my menu colors also changed.

I recommend checking out the theme development guide on the left. You will most likely need to create a 'new' definition for the specific links you want highlighted in a given color.

you would need to edit the newbb files and change the name of the class for the section dealing with links etc (i'm not sure exactly what to change as i don't use newbb)

then insert a new class in the style.css with the same name as the class you renamed to in newbb and set the colours there..

I have no idea if it is actually possible to do this way as i've never tried it using the forum, but i have done this with other modules on my site.