You're doing too many hacks to your computer... be careful if you don't understand this stuff. Be very careful with chown... don't even mess with all this changing icons and showing hidden files unless you actually know what you're doing.
Chown would not create .css files. It might have led you to be able to see the hidden unix folders, although it should not have.
I would:
1) Open a terminal and do this (
source):
sudo defaults write com.apple.finder AppleShowAllFiles FALSE
killall Finder
This will stop the /etc /var and so on from displaying.
2) Open Disk Utility and repair permissions. This will undo any damage you did with chown.
3) The .css files are sort of like template files for the web. They shouldn't need to be there. They might have ended up there because you installed a web development or other application to an unusual place (like I noticed you have FCE in the root of the hard drive for some reason?). You can just delete the .css files. If they show back up at a later time, watch what application you're running. That application is probably installed in the wrong place or has the wrong preferences and is putting them there.
Then make sure everything works normally. If possible, go back to just installing applications in the applications folder instead of weird places. The permissions and ownership of the root folder are not appropriate to storing apps.