Instead of duplicating it just override what you want.
For example suppose you want to override this:
Go into Page Settings and put a custom css class on the page where you want your faq. For example name the css class myfaq. The class will be applied to the body element.
Then you can override the style on that page like this:
this makes a more specific css selector to make it possible to override style rules.
just make sure that the css file you put it in is lower in the list in style.config so it comes after the style you want to override.
Hope that helps,