I'm learning jQuery-UI, and would like to put together a good looking page, so I'm looking at base2.css from the themeroller site.
Q: Is there anything anyone can tell me about base2.css?
Is there any documentation on it?
How much is specific to only the themeroller site itself, and how much of it is useful for sites that use themeroller themes?
base2.css is just a bunch of styles specifically for the jQuery UI site in general, you'll find it's included on the documentation pages, bug tracker, support center, etc. It isn't really theme-roller specific at all, this css is though.
What you want for themeroller themes is this css: http://jquery-ui.googlecode.com/svn/tags/latest/themes/base/jquery-ui.css
That css file is the base grey theme, then you customize on top of it. However, themeroller packages everything you need in a single theme, so you don't include the base theme then another stylesheet with certain customizations (though you could!), rather you include the single .css file it generates for you, which includes all the styles.