Optimize existing mobile webdesign for Android, iOS and Windows Phone

For a client, I'm creating a mobile webshop from an existing webshop, and it's almost done. However I'm having slight trouble getting the rendered code adapted to the 3 platforms: Android, iOS and WP. Your job: fix the HTML/CSS of the mobile site, so it renders nice on all 3 platforms. Requirements: - you must have a proven track record in mobile webdesign, references needed - the final result must comply to XHTML5 - must be able to start the job at once Interested bidders can get access to the site, and see what's need to done for themselves, by messaging me.