[dreyfiz]

A custom build with only the components you're using cuts the CSS size dramatically. You also get to specify your supported browsers, which can cut down the size as well. Finally, you don't have to use their javascript, and not every component requires it.

[nkkollaw]

Somehow we were unable to reduce the file size to a sane level and we switch to another framework. I guess we needed some components and we had to load jQuery as well.

In any case, wouldn't it make sense for the default configuration to be suitable for the average project? 500KB is really something...