Unfortunately Expression Web does not understand root relative urls so the latter will not work. In Expression Web all links have to document relative. If you are using a DWT then your stylesheet links will automatically be updated to document relative so in a subfolder the path would be "../css/name.css".
If you are using master pages you use "<link rel="stylesheet" type="text/css" href="./site.css" />" Though personally I prefer to put my site css in the root instead of in a subfolder since I've been using CSS long enough to remember browsers that had bug with file paths in CSS if the file was in other than the root and others that would not use a css file that was outside of the root so it probably is just habit.
On a side note, what do you think of the new forum version?
Cheryl D Wise MS MVP Expression Instructor: starttoweb.com