Design four themes for dynamic Web site

I have a dynamic Web site that hosts multiple subects in a single database. Each subject requires its own CSS-based theme, including incidental artwork for backgrounds and borders as well as space to locate unique user-supplied graphics, like a banner and logo, of a specified size. I need the CSS elements of the site refined and documented so that additional themes can be created for the site. Then I would like four demonstration themes created using CSS: two highly stylized, one optimized for mobile browsers, and one additional theme that is optimized for the vision impaired using a screen reader. [login to view URL] The back end of the interface is essentially complete. This includes the PHP coding that accesses the database and delivers the appropriately html tagged data for different sections of the site. The front end has been created, but the programmer graduated (don't you hate it when great things happen to your critical employees?) The front end may need additional work with regard to HTML and CSS tweaks needed to tighten up design and display elements. That said, the frontend does have the required functionality. What it really needs is someone with HTML, CSS, and maybe some Javascript experience to clean it up a bit. The site has a whopping three pages. Please, only bidders with significant CSS/theme/design experience.