a4j:loadStyle is similar to the standard style tag with src attribute, but it allows
to load a style sheet file from alternative sources like a jar file.
src attribute defines the context relative path to the style sheet file. Instead of html
style tag it's not required to have a prefix in your application. The leading slash in
the path means the root of the web context.
You can use "resource://" prefix to access the file using
RichFaces resource framework. For example, if your css file is located inside the
jar file and has a full path there: /org/mycompany/assets/css/common.css, you can
point to it with:
Richfaces allows to have a dynamically generated css file based on RichFaces
skinnability feature. xcss is an XML formated css with some additional extensions.
The following example shows how the look-n-feel of non-RichFaces components might
be changed based on the selected skin. The panel with the form elements consists
only of non-Richfaces component, but it is sensitive to the current skin.