If you have a folder structure like follows:
/public_html/
/css/
/images/
/index.html
Then your CSS should work.
- Starting with "/" returns to the root directory and starts there
- Starting with "../" moves one directory backwards and starts there
- Starting with "../../" moves two directories backwards and starts there (and so on...) To move forward, just start with the first
subdirectory and keep moving forward
Read more here: http://css-tricks.com/quick-reminder-about-file-paths/