Global CSS is a strong tool to adjust the styling of a complete website. It would  be nice, if you can integrate a dropdown selector with thumb preview for embedding external css files.

Attached you will find two screenshots
1. A suggestion how to implement it in bloxby
2. A existing solution created by us for an open source ticket system

As you can see in the second screenshot, we implemented a dropdown google font selector for headings and body. Please ensure that the settings are stored in revision and the embedded css is visible in editing mode.

Best regards,
Jürgen