The title says everything about what I'm looking for. Basically it should be an software that collects all styles of a website so I can edit them and save them.

Please read the question carefully, because I want all mentioned conditions to be met.

EDIT: I want to be more clear here or rather describe my desired workflow. Starting situation will be that you have the sources of the website on your local machine.

Now I want to open the plain sources (HTML/CSS) in my editor/IDE/whatever (no WYSIWYG!). And I want a live preview right next to it or in different window (not in another tab!), I want to see it as I edit the source. The preview should be updated automatically (or when I save the file which essentially would be the same because CTRL+S is kind of a reflex :P).

Additionally it should have an inspector that works like those in Firebug or Chrom(e|ium). When I click on a CSS selector in that inspector, the cursor should jump right to it in the respective source file.

ANOTHER EDIT: Found this https://stackoverflow.com/q/4680109/220652. Almost the same problem.