After the layout data has been given a structure, it is next given a theme and a skin. Simultaneously to this, the channel content is rendered. All of these are put together to form the final markup that will be viewed by the user.
The theme defines what device; a web browser, a PDA, a cell phone, or some other device, will be used to view the page, and the skin is the color scheme, text styles and images that give the layout its look and feel. To apply a theme to the layout, the XML output from the structure stylesheet is transformed through a second XSL stylesheet. This stylesheet converts the structure into a final output mark up, such as XHTML for a web browser or WML for a cell phone. Similar to the layout data going into the structure, many different theme stylesheets can be written to view the same structure on multiple devices. Below is an excerpt of an XHTML theme output.
Themes can be modified to output different markup - e.g. a custom header, or specific HTML for channel borders, or navigation al elements.