YUI App Theme – it’s a generic, skinnable layout designed for web applications, particularly admin areas. Built using YUI Grids. It offers a tabbed layout with many of the common UI elements that web apps need. Content blocks, tabbed modules, one and two-column forms, error messages, etc. Most importantly it’s built using YUI Grids so it’s semantically structured, cross-browser, and easy to extend. You can radically alter the layout with just a few quick changes. Explore the demo page