It changes the background of the Google docs from eyeball destroying white to a pleasant dark grey or black and doesn't mess up the overall theme of my browser or any other websites (unlike other add ons I've tried), nothing too fancy, doesn't have a hundred unnecessary features that cause crashes or slowing down, simply does what it's supposed to do: spares my eyes from the default google docs background white, nothing more, nothing less. Exactly what I needed, thank you.