Welcome to the official community for LibreWolf.
LibreWolf is designed to increase protection against tracking and fingerprinting techniques, while also including a few security improvements. LibreWolf also aims to remove all the telemetry, data collection and annoyances, as well as disabling anti-freedom features like DRM. If you have any question please visit our FAQ first: https://librewolf.net/docs/faq/
To learn more or to download the browser visit the website: https://librewolf.net/
If you want to contribute head over to our Codeberg: https://codeberg.org/librewolf
You can accomplish this using userContent.css stylings.
Dark mode for the pdf itself can be accomplished by following this blog guide.
Once set up, you can then paste additional stylings to get the background and sidebar whatever color you prefer. Here is my userContent.css.
The commented out lines towards the bottom are for the sidebar (I personally didn't change the sidebar).
Hope this helps.
thank you very much, it worked really well