There're plenty of CSS framework available, the most famous one would be Twitter Bootstrap. Bootstrap has everything you need to create web UI easily and quickly, it has all the UI components and javascript as well.
However, not everybody needs all those features. If you're looking for simple CSS framework, let me introduce Vital to you. Vital is built to be lightweight and flexible, as a result, many web application can use it as a backbone CSS.
Components
Here're some of the components in Vital CSS framework
Grid
It's bundled with a CSS grid. You can either specifiy the columns you need or using the Automatic Grid - it will assume you want equally sized column. It lacks of grid preference for different viewports, something Bootstrap has.
Notice
A standard UI for notification.
Buttons
A few size, shape and fill options for buttons.
Form
To ensure cross platform consistency, form is all styled up to appear identically across different browsers.
Other
You will also get Navigation Header, Tables, Pagination, Tab, Font Icons, Loaders and Typography.
Comments will be moderated and
rel="nofollow"will be added to all links. You can wrap your coding with[code][/code]to make use of built-in syntax highlighter.