Here is one example:
You have panels that display content from HTML memo fields. These include links to web pages (A HREF links). Once a user has visited these pages, you want the colour of the link to change to red.
This piece of CSS code turns links red once visited. Any links in HTML memo field content displayed on a model that includes this Generic XHTML action panel will turn red once visited.
Note that this CSS will not affect Hyperlink controls (on the ribbon, on the Home tab, in the Insert
group, under More, there is a Hyperlink control).
The full document can be found via the attached word document.