Thank you everyone for the fantastic comments. :)
To everyone who asked for examples: Unfortunately, I can’t show you any of my real-world examples, because, well, I’m not allowed to. :) I’ll get a sample version up (hopefully in the very near future), and update everyone in the comments here when that happens). In the meantime, here are a few online elsewhere that I have used as inspiration in the past.
The others I use for inspiration are printed, so unfortunately, can’t share them. Thanks for the examples shared in the comments. To those discussing CSS variables, I think it’s an interesting idea, but I’ve never had the opportunity to use them. I can’t really give an opinion on it.
@Niek — disabling the ability to make changes would appear to be the ideal route, especially if you are the one to continue maintaining the site. However, if the site is commissioned over to the client, in that it is now in their care, that method seems a bit restrictive. I guess it depends on the situation.
@Robert — Indeed. The more detailed you can make the documentation, the better. No worries on being bitter (regarding lack of tools to make this more streamlined). I want that very badly, and have even been thinking up some ideas… ;)
@Mark — It might be unrealistic for some projects, but I encourage you to make it a part of the project. Some clients might not see the need for it, but I think it’s a good idea to sell them on the benefits. It’s like a handbook or manual for their product you just built for them. :)
@Brian — Thanks. A book? One day. ;)
@Brett — Worthless? I think that’s a matter of opinion. I have always found web style guides to be very useful (even if in print). Especially if I’m a new developer/designer joining the team on a project — I have something to refer to. I do agree that for the web, it makes more sense to document on the web — I already stated in the article that doing this online would be beneficial.
@Matt — I agree, an online style guide is preferable than a printed style guide. It’s also better for the environment! However, sometimes I need stuff in print to jot down notes or pass around. Simple print style sheets should do the trick.
@Todd — Unfortunately, that is a problem I am faced with as well. However, I find that when people come to me with questions, I refer them to where the documentation is each time. It reinforces the idea that the documentation is the best source.
@Bjarke — Time is certainly an issue. In my experience, making it part of the project has helped, though I agree, not every client sees the value in this. Perhaps a reusable template would work to help save time.
@John — You’ve read my mind. :) Thanks for the resources.
@Christen — Yes. This would be a good thing to “templatize” so you can reuse it.