Penumbra: Darker Notes Mod addon

Copypaste of the readme file:

Go to the Penumbra directory (Right click on the left side of your Steam library, manage, browse game files)

/common/Penumbra Overture/graphics/notebook/

Navigate to the filepath here

Copy the files from this directory to that place, replace any existing files.

REVERTING CHANGES:

Just delete the dark notebook files (3 of them in total) and delete the "_backup" from the light theme files, then restart the game.