Mark,
I haven't had a chance to examine openacs5.x's css yet, so cannot comment directly.
Cross-browser, multi-column css formating should be possible, much depends on whether the style assumes fixed positions or flexible (releative to window size).
I'm working on a flexible generic multicolumn style for another site, and will make suggestions once I have something tested (on macs etc.).
Mark, how does the "corners and borders"[1] and 3column flexible style[2] below work for your browsers?
They worked for the MacOS X and 9.1, NN and IE I have access to.
Torben
1. http://www.redmelon.net/tstme/4corners
2. http://www.redmelon.net/tstme/3cols2/
