I don't advocate using it, I just posted it for historical reference (actually I'm hesitating to post anything LISP here because that will easily derail a thread into becoming off-topic).
But what the snippet shows is how eg. the DOM is traversed explicitly, as opposed to CSS's multiple implicit measurement and layout passes over the DOM. CSS sure is more compact, but doesn't begin to reveal anything like the above snippet.
For one thing, if the rest of the representation of the document (the HTML and script part) was in the same language, maybe the CSS could be condensed with macros, or otherwise procedurally generated on the client side, all in the same syntax.