I have seen all these 'grid' type css frameworks and I'm still a tad confused as to what they do.
I understand that they help you quickly create a page since the layout is already defined for you, but do these frameworks make certain things MORE difficult?
It depends on how you typically use CSS to set up your pages. They wind up using less semantic classes ("indent-12" vs. "rail-content") if that's important to you, but they also solve a lot of layout issues people tend to run into.
They take care of the need (mostly) for floats, which can break designs faster than... well, something fast.
What they make harder, however, is customization. If you don't take the time to learn just what those classes mean, it can be hard to make things look just the way you want because your CSS rules might clash with something you didn't know about.
They are great as a way to switch from tables to CSS-based design, and they also really help implement the "grid" theory of design, where things line up and are in horizontal and vertical rhythm.
Take 'em or leave 'em (I left them, but sure played with them a bit)
EDIT: I used both 960 and blueprint, about 8 months ago or so. Unclear if significant changes have taken place since then.
Grid 960 is a CSS framework. Mainly, it can help you develop faster the mock-up of your page.
You can learn more about it in this tutorial.
Enjoy!
I have looked into various CSS frameworks in the past and I think they are aimed at removing a lot of the nitty CSS bugs that come across between browsers, if you ever tried to hand roll your own CSS you will know the issues that come up. If you have your own template that you have developed I would stick with it, that is what I ended up doing. I am familiar with it and it is very lightweight.
A 960 grid is a framework that should be implemented from the initial design stage. It helps both the designer and developer create clean organised UIs. In my experience the 960 grid system (http://www.960.gs) has helped a lot as it will allow me to create a formatted page quickly without re-writing any css files no matter what a client asks for. Typically I implement CSS styles like the following
.marginLeft20 { margin-left: 20px; }
.oneColumn {
float: left;
width: 60px;
}
This means I can make a div with the above classes applied
<div class="oneColumn marginLeft20">This is a oneColumn example</div>
If you need anymore info on grids I would recommend http://www.960.gs
Grid systems/frameworks are sort of like a sandbox with all the shovels, pails, sand and shapers ready made, so that all you have to do is pick up a tool and start making your castle.
Burt makes a great point about rolling your own CSS and all of the browser issues you run into. It can make for a very frustrating experience depending on the project you're working on!
While the framework you're using may have some limitations, it alleviates some headaches also.