This is somewhat related to my security question here. Is it a bad idea to use an hg / mercurial repository for a live website? If so, why?

Furthermore, we have dev, test and production installations of our website, like dev.example.com, test.example.com and www.example.com. If it's a bad idea to use a repository for a live/production website, would it be OK to use an hg repository for the dev and test sites?

I'm also concerned about ease of deployment. We have technical and less technical co-workers who will be working with the site. The technical guys (software engineers) won't have any problem working with the command line or TortoiseHG. I'm more concerned about the less technical guys (web designers). They won't be comfortable working on the command line, and may even find TortoiseHG daunting. These guys mostly upload .css files and images to the server. I'd like for these files (at least the .css files) to be under version control, but I want this to be as transparent as possible for the non technical guys.

What's the best way to achieve this?

Edit: Our 'site' is actually a multi-site CMS setup with a main repository and several subrepositories. Mock-up of the repository structure:

/root [main repository containing core files and subrepositories]
    /modules [modules subrepository]
    /sites/global [subrepository for global .css and .php files]
    /sites/site1 [site1 subrepository]
    ...
    /sites/siteN [siteN subrepository]

Software engineers would work in the root, modules and sites/global repositories. Less technical guys (web designers) would work only in the site1 ... siteN subrepositories.