I am trying to create a dummy site to test out some new designs. I copy my files into a subdirectory, however, the files in the subdirectory are still linked to the stylesheet in my main directory. How can I change that?

For example, if my subdirectory is called "demo", I want all the files to be linked to the stylesheet in the demo subdirectory, not to the stylesheet in the main directory.

Thank you in advance for any help.