I've put together a new design, and started adjusting the Increase/Decrease font size options, which currently do not work on the published site.
Just so's you know, the way I've chosen to do this is to adjust the font-size CSS attribute of the body element. So long as all internal font-sizes are then specified as percentages, this single adjustment can alter all the necessary formatting options.
Unfortunately, since I uploaded the site only half-way through the process, several items/modules are somehow broken. My Expression CMS currently generates "/journal/" pages which are not valid, since there's an issue with an anchor, which I wasn't really thinking about when I typed up. My local copy's fixed this and most other issues... I just haven't actually uploaded it yet :/