decaporg/decap-cms ? reverse-engineered prompt

Build me a simple Git based CMS that I can add to a static website so non technical teammates can edit content without touching code. I want it to live in an admin area of the site, ask people to log in, then let them create new content and update existing pages or posts that are stored in the site repository.

Please make the admin experience feel clean and straightforward, with the content types driven by a YAML config so I can define things like blog posts, pages, and fields without rewriting the app. It should work as a quick drop in option with a basic HTML admin page and config file, but also be flexible enough for a more advanced setup if needed.

The main goal is that editors can go to the admin screen, sign in, and manage content, while everything still fits a static site workflow and stays in Git. If anything is unclear, look up the current Decap CMS docs online and follow that approach.