Starting with Responsive Web Design, fancybox?

I’m redesigning a website that uses fancybox. For example, it uses fancybox when a user tries to register to the site or login (a fancybox window appears).

I’d like to start using a CSS Framework like bootstrap or Pure. The question is, what do I do with the fancybox? Is there anyway to detect it and adapt it? What are the best practices?

Many thanks.


I’m afraid I don’t know anything about fancybox but if it’s this one then it appears to be responsive already.