Made some significant steps today:

1. Rewrote the XQuery that retrieves a poem in XML, so that it also harvests all feature structure elements from the feature_system.xml file which correspond to abbreviations in the text of that poem. This goes some way towards giving us a working independent XML file for each poem, which is good in itself, and gives us the basis for rendering info about the abbreviations.
2. Added rendering of the abbreviations to the XSLT. What this actually does is to provide a visible span with the expansion, followed by a (normally) invisible span containing details harvested from the feature structures in the header.
3. Added CSS code to support the abbreviation code.
4. Added JavaScript to show the information about the abbreviation. Spent a while tweaking this so that it looks reasonable even when key pieces of info are missing (which is often the case).
5. Tested on all the regular browsers -- no problems, except for some anti-aliasing issues on IE7, which probably aren't worth worrying about at this stage.
6. Added more meaningful menu, with links to the DMS home page, the poem index, the blog and the wiki.

Next we should make it look a bit prettier, and after that, perhaps go back to the idea of the slow fade.