I would like to know how I can customize WordPress to set up different user permissions. I would like to create a WordPress theme that will have say five departments namely
Math | English | Science | Music | Computers. These will be represented by the navigation menu. For example the nav tab named Math will be navigation item as well as a name representing that math department.
Each department say the Math department will have a number of users and only one person from that department will have the privilege to add, edit or delete content only to their page/department and not any other Page/department.
Also and more importunately, I want to know how I can customize my WordPress theme so that I control how much HTML or CSS each department can use. For example, I want to limit access to HTML and CSS code so that users do not add code that will break the layout of the site.