You can use UI Style Guides, we can separate the visual language of a website from the structure. Something which is often difficult for clients to do when they are presented with a complete mock-up. It becomes possible to make quick and easy changes to the layout without needing to worry about the styling. And likewise if the client wants to make changes to the visual language, it can be done without worrying about updating multiple elements across multiple pages.
This article was published 10 years ago, therefore the contents of this post may be out of date.