Sass Compass multiple themes ruby on rails

I have a rails app that is a sort of CMS and i alow users to create their own version of the applicaton on a sub domain.

I also want to let them style their app version the way they want but changing a few开发者_开发技巧 fields or small config file.

I was hoping to be able to use sass and compass and be able to let users change varialbes for there own style.

How can i do this ? is it possible as saas needs to be compiled to css when varialbes are changed. i think?

Is there a better way ?

thanks alot richard moss

It's possible to use Sass functions to access the outside environment; see the Sass documentation for details. Before you do this, make sure you'll be properly caching your stylesheets so that they don't need to be regenerated for every request.