I am evaluating CCS grid frameworks for web sites, blogs, and CMS-based sites, and have looked at Blueprint and Yahoo's YUI. They both look good, but it is not so easy to change the column sizes or spacing. And they both add a lot of weight to the first page's download.
Are these the best, or are there other frameworks that are more flexible or more lightweight? Which frameworks integrate well with Wordpress or Drupal?
I've used 960 before with success (960.gs). It takes a little getting used to since you can only use 12 or 16 columns, but it's very lightweight and ultimately works pretty well for the sites I've used it on. Of course, it won't work for all designs, but it's still pretty flexible.
You mentioned Blueprint http://www.blueprintcss.org/ and that's my favorite. Of course, many people will tell you to create your own (which is not a bad idea if you have the time.)
I've used the 960.gs framework extensively. It's very lightweight and gives a good initial framework for you to build on.
Both Blueprint and 960gs are great, but you seem to want more flexibility in defining grid width, column widths, and margin widths. 960gs is fairly constrained in this sense although its defaults are positioned at a very useful and popular grid width.
Blueprint, however, has the benefit of the Blueprint Grid CSS Generator. With the grid generator, you define your desired number of columns, column width, margin width, and it generates all the Blueprint CSS classes. It will even compress them for you and generate a background grid image file for you. You get the benefit of a grid system plus the flexibility of grid adjustments.
Edge: Blueprint + Blueprint Grid CSS Generator.
Update: Spry-Soft now offers a 960gs Grid CSS Generator which narrows, if not closes the gap between the two.
YUI Grids from Yahoo YUI library is pretty flexible, although you need to add non-semantic divs to give hints for the layouts. The nice thing is that out of the box there is support for different column widths on the left or the right and standard 1/2-1/2, 1/3-1/3-1/3, 1/3-2/3, 1/4-3/4 layouts which can be nested as well. Also nice is that the divs can be laid out in your markup independent of final location on the page.
You can reduce the compressed 960.css by another 1K by replacing:
container_ with c_
grid_ with g_
suffix_ with s_
prefix_ with p_
Won't be pretty but if you're desperate for another 1K :)
I would go with 960.gs (or the Golden grid system) - I've used it in many of my projects successfully. Recently I found a generator that will give you the option to define the width etc. for your grid systems. http://www.gridsystemgenerator.com/
The trouble with grid frameworks is this. They start of to make it easier for a designer to quickly layout a page and then try and do too many other things.The result is added overhead with no payback. These things have all come to the fore at the same time as Google is encouraging us all to make out pages load quicker. Yes once the css files are in the browser cache there's no difference but that first time first page load is an issue. If you don't know what I'm talking about go to you Google Webmaster Tools page and go to Labs>>Site Performance. They encourage you to use a Firefox extension to analyse your pages called Page Speed that sits on top of Firebug. When you use this to analyse your pages the second thing in the list of suggestions is "Remove unused CSS".
I am therefore searching for a robust lightweight framework.
There is a 1k grid system grid generator. It is super easy to use and is only 1k in size. that is with the comments added in it. with the text and the reset it brings the total to 3k. you can find it at http://www.gridsystemgenerator.com/gs03.php