I'm a web developer/designer. I have a client who's looking for a good visual editor so he won't have to come to me for simple weekly maintenance stuff. I know this seems like something that I would want him to be able to do, but trust me, he'll still need me. He's pretty technologically illiterate.

Here's what I need it to do: work nicely with external stylesheets (written in CSS3), avoid messing up my PHP and Javascript work; and allow my client to add, remove, and change text, pictures, and videos, and other content. I'll still be doing the major updates to the PHP, Javascript, and associated functions (like pictures in a slideshow). He just needs to be able to change some of the static content without screwing everything up.

The editor would need to be able to open a .php file and its associated external stylesheets with minimal technological knowledge required, edit the images and text used on the website, all without accidentally messing with the Javascript and PHP.