Modify permanently a CSS of a website that I do not own, and distribute the change to my network

Question

What is the easiest way to do it?

I have difficulties to understand and not having now enough time to spend and study Greasemonkey properly, to just apply a PERMANENT css change to ANY website.

I thought that was more easy, to just add a CSS that would stay with the browser. But I do not find any easy/quick tool customization to just add a simple .css file to do my changes.

For example I would like to restyle Twitter, because I hate the new design, It is killing any kind of graphic personalization that I would like to have.

I need it simple, because I want to let people with not high tech knowledge, to be able to get my personalization, implement it and do it as well.

I know that this could have a security issue, but all that I want to do it is add a piece of CSS, and not additional Javascript functionality.

EDIT: Possibly that could work in all the browsers, not only Chrome and Firefox (I know that might not exist, but I would like to have an alternative for people that use IE)

I am an expert web designer, but I am not a programmer. Outside Javascript I do not script anything else.

Answer 1

Install Stylish. Make custom CSS file. Winning.

Answer 2

You're looking for the Stylish extension.

Answer 3

You can add a user stylesheet in several major browsers that will override the site stylesheet. It will require a good working knowledge of CSS though and for firefox you have to create the file manually in your profile.

http://www.squarefree.com/userstyles/user-style-sheets.html