I believe there is no copyright on fashion just fashion LOGOS and labels. That is why knock offs exist and designers make the same thing just calling it their own.
I can tell you that the famous red sole shoe won a trademark dispute with Yves St. Laurent. The shoe has to be a contrasting color to the famous sole to be included in the trademark.
All red is good to go.
A design patent protects the shape, style, color, Etc. Utility patents cover function. Thus a Chevy HHR can look very much like a PT Cruiser, but it’s not exactly the same. Whether fashion houses patent their designs I don’t know.