File Structures And CSS

When starting the development phase (html, css, etc) of a web site, one of the first things I create is a file structure. Typically, this involves creating two basic folders…

• /images
• /includes

…all the content pages are stored at the root level, while images naturally go in the images folder and all of the included code elements (header, footer, menu, etc) go in the includes folder.

However, where do you put the css files? Should they be dumped in with the images, since it’s part of the site’s design/presentation? Or, does it belong in the includes folder, along with other snippets of code? Or should it belong somewhere else entirely?