Question: I were looking for a CSS Framework to help me built website, when I struck with *Compass*.

Now, while I understand what a CSS Framework is, I don't understand what's a CSS **Authoring** Framework.

Expecially, I don't understand if it "replaces" a CSS Framework (like blueprint) or you should use it **with** a CSS Framework.

I'm building a website using Ruby On Rails, and I use SASS but no CSS Frameworks at the moment. If anyone can point me in right direction after answering the question, it will be really appreciated.

**Edit 1:**
Also, which is the difference between a CSS Framework and a CSS Authoring Framework

Answer: 
A CSS Framework is (in most cases) a fixed set of basic CSS definitions.
f.e. it brings definitions for some classes which make a basic div-based HTML-layout usable for different screen-widths. (aka liquid layout)

A CSS Authoring Framework (in meaning of Compass) brings no fixed set of CSS definitions. In opposite to a standard CSS Framework, it helps to write CSS rules with various helpers - but you have to write almost every CSS definition by your own. Some examples for helpers: Compass helps you to fix some [common browser issues](http://compass-style.org/reference/compass/utilities/general/clearfix/) ([IE floats ..](http://compass-style.org/reference/compass/utilities/general/float/)). And you can [create CSS sprites](http://compass-style.org/help/tutorials/spriting/) from existing images with all the CSS definitions on the fly.

You can write your own CSS Framework with the help of a CSS Authoring Framework, or you can simple build on top of a existing CSS Framework.
CSS frameworks are pre-prepared libraries that are meant to allow for easier, more standards-compliant styling of web pages using the Cascading Style Sheets language.

Layout-grid-related CSS frameworks include Bootstrap, Blueprint, 960 grid, YUI CSS, and other grids.

Like programming and scripting language libraries, CSS frameworks are usually incorporated as external .css sheets referenced in the HTML .

They provide a number of ready-made options for designing and laying out the web page. While many of these frameworks have been published, some authors use them mostly for rapid prototyping, or for learning from, and prefer to 'handcraft' CSS that is appropriate to each published site without the design, maintenance and download overhead of having many unused features in the site's styling.

Somehow, CSS framework == CSS Authoring framework