Thanks! These are some of the questions we've been mulling over. We are working on importing existing CSS, but as far as importing the framework - that's another hurdle. We will be giving our designers either choices of frameworks to work from (bootstrap, foundation, etc) when creating a new website or our own framework - it all depends on the goal of the designer (to export the code or continue to use Webflow to build the website). Really, our personal goal is to give designers the best tools so they don't have to worry about frameworks. All they have to do is design and everything just works.