PHP codeignator developer for building automatic creation of websites for each seller.

we have website for customers and seller, which is build on PHP code-ignator, now we want another functionality, where seller can create their website, with nice slides on home page, home page only differs for each seller as they can design their own, remaining pages information need to retrieve from data database. like list of products and address and about us, such a details. seller able to sellect logos which are freely available in website and othe pictures which are free, and able to upload the pictures in their own, and also, with small variance seller can change their home page looks totally different from other, like color schema and slider display design header display design such a things, same way need to do for mobile as well.