Do you know where to add style files for SharePoint deployment?

When a designer (or a developer) adds style (CSS) files to SharePoint - care must be taken regarding where the files are placed:

• Some places are are not suitable because they are not good for deployment
• Other places may have permission issues - designers can't access them
• Some files are part of the site definition and should not be customized

So the rules are:

1. Never modify out of the box SharePoint files in /Style Library/ - those files are part of the site definition, if you customize them they are hard to deploy
2. Start with a clean, minimal masterpage
3. Create and reference your own CSS files and put them under /Style Library/CSS/<client>/
4. You may want to further divide your CSS paths according to the areas of the site that your CSS is designed for:
   E.g. /Style Library/CSS/SSW/Clients/layout.css
5. Designers can modify the XSL file as well! Put them under /Style Library/XSL Style Sheets/<client>/