Having taken a week off work, I have belatedly updated the CAPTION 2004 web site. It includes tabbed sections using a technique taken from the article Sliding Doors of CSS on the A List Apart web site.
In fact I did not just steal the technique, I stole the exact same graphics (rather than drawing up my own) since the colour and shape were right anyway.
The backgrounds use a picture by Carla plus Eric Meyer's 'Complex Spiral' technique for creating the illusion of translucent backgrounds to the text (the text should look like it is printed on translucent rectangles hovering over the background drawing; this will not work properly in Microsoft Internet Explorer, however, so I might have to take it out).
I have also shamelessly switched to using Unicode's typographically-correct quotation marks: 'thus' rather than ASCII-era ersatz punctuation 'thus'. I am hoping that this will not attract too much approbium.