patpatpat on "center everything with wrapper in style.css"

Hi,
i would like to center the whole content of the side in a box with a width of 1000 px. I'm new to it but tried and googled a lot. But the wrapper is just being ignored. I don't see the red frame (for testing) and the change of width has no effect at all. Do I have to include "wrapper" anywhere else in my theme beside the css? Is "wrapper" a keyword in wordpress or do I have to refer to it? Thanks a lot. This is my style.css:

[Entire stylesheet deleted - that's way too much code to post here]