A complete re-write of my old Infinite Dark mod for 1.12.
Adds a completely dark block, slab and stair for cosmetic purposes. Also adds a block that is dark on one side and glass on the other 5 sides. While holding a dark item, the dark blocks become less dark so that they are easier to see.
There are config settings to adjust the brightness of the modified dark texture, as well as settings to use a keybind to modify the dark texture instead of changing the texture when a dark item is held.
Feel free to leave suggestions.