How it works

The way xdv works is simple, but since it might take a little adjustment of the mental model you're used to if you have done theming in Plone (or any other system), it's worth an explanation:

The main difference is that you're not touching the templates and HTML from Plone itself at all. Instead, you create the layout and design you want in standalone HTML and CSS files — and then map parts of the content that comes out of Plone into your existing HTML.

This means that you can create as complex (or simple!) designs as you want, and let Plone supply the content.

This also means that you can write your own from-scratch HTML and CSS, but also map various Plone elements to wherever you want in your own design. Plone knows nothing about what happens "on the way out", it just renders a page as it usually does.

A more visual way to look at it, here you can see how the Plone output is mapped into a totally different template and design:

This makes for a much more robust approach to theming, because as long as Plone keeps its HTML classes and IDs the same from one version to the next, your theme will automatically work even in a new version of Plone. And if it has changed, it's a relatively simple operation to update the theme — just locate the new name, and replace it in the rule file.

Let's take a closer look at the rule file.