I heard of an option to build websites by creating a static html/css/javascript front end and connecting that to a WordPress admin side or even an excel spreadsheet where the admin add content.

I think this would be amazing but I don't know anything about it yet. I first thought it was something new from WordPress 4.0, but I don't even think it's related to 4.0 because I heard that can be done even with Drupal admin.

So essentially you log in and put the content in Drupal or WordPress but the front end is not a Drupal or WordPress theme. It's just a static site in which the content is fed.

Does anybody knows something about this? Any place to look for where they talk about it or explain it?

Thank you very much in advance!