That sort of depends, but for the most part CSS frameworks can provide:
- Sensible defaults for sizing and other attributes that tend to differ across browsers, including typography and such (see Y! CSS Reset)
- Helper classes for forms, info boxes, so on (see Blueprint's forms.css)
- Grid-based layouts to cut down on dev time (see Y! Grids)
Basically, they attempt to cut down on CSS development time by making things equivalent across browsers as well as providing many common styles you would have made anyway. Some also provide various grid-based layouts and others go beyond these things to provide even more, effectively creating something that truly is a framework (I prefer to think of most of them as CSS libraries).
A CSS framework are a collection of files that provide defaults for you to customize or build upon when your writing your stylesheets. Whether its typography or page layout widths or grids/columns, the main point of a framework is to cut down on development time by providing you a base that you can build upon and customize.
I can't say for sure why you may want to use one, that really depends on the project at hand. One argument can be that you can just run with it without having to define and test your own styles. Also, a framework can eliminate a lot of cross browser issues that may arise and give you consistency across a wide range of browsers.
Seems to me that's a CSS framework without the useful parts.
Looks like just a reset with "sensible" styles that look terrible in my browser and don't seem like anything I'd use myself. Why not make use of the "C" in CSS and separate "reset.css" and "sensible.css", or at least declare the styles twice to distinguish between removing styles vs. adding styles? I don't get mixing the two.
Oh, and putting Arial before Helvetica is just shameful. Not just because Arial is shameful, but because every system that has Helvetica (i.e. Macs, some Windows users) also has Arial. So as written, Helvetica will never be seen. Likewise for Courier New vs. Courier, or Times New Roman vs. Times. It's nice to declare fonts that look best on each platform, but only if it actually works.
the text on that page doesn't fit properly inside the horizontal lines on firefox/unix, so it doesn't inspire much confidence in it as a css framework.
Looks good in FF3.0.4/Linux, lines up perfectly all the way down the page. I have no zoom, and I have zoom-text-only turned off. Can't tell which font it is (as I'm not a typeface nerd), but I think I have all the ones listed in font-family installed. But using a background image for those lines could be considered anti-accessibility and anti-readability anyway.
Edit: the sample HTML file gets unaligned after the table, but I think that's because there are some 0.375em paddings scattered around in there (turning those off seem to shore it up nicely).
I'm not going to ditch Blueprint for it - I like being able to columnize very easily, and it's not a pain to change column size/number - but Blueprint (and 960gs) could definitely take some ideas from this, like not being redundant.
