Wow! this is totally amazing! I've been seeing this in a few places and have been waiting for someone to come up with a plugin for WordPress to make this easier!
I do have one quick question, how could I target a particular div, on my homepage I have a full width div set to a height where I would like to overlay other divs which contain call to actions etc.(the page then needs to be able to scroll vertically) It would be awesome feature if on the settings page if you could apply all your code to a particular div ID.
Im not sure if this is even possible as im not a hardcore developer :)