How to create UI framework agnostic Website/Application

I started using UI framework when I was first introduced to skeleton to help with responsive behavior and stuff. Then I moved to Bootstrap as I felt it offered little more than skeleton. Now I like Zurb's Foundation and its features. Though what stops me from easily (or relatively easily) switching across different framework is I add the framework specific styles to the code itself, like css class, btn, row, spanX etc. Now every time i like to change the framework I need to go to the code and modify every single instance. I build the applications mostly on Rails and Node.js. Is there any tool/ approach out there that spare me from having to modify the source code, one that will allow me keep the styling information mark up separate so that I only change those when I make a switch? Appreciate your inputs.