Very useful Add-on but I had to uninstall it. When the app is disabled it still formats text. I have to enable it and then disable it for the original page presentation. At first I thought the add-on created a registry of visited urls and saved their settings, but that isn't the case. It would, however, be a great feature. I would continue using this add-on because I agree with the developer's premise: light gray text on a white background is completely insane. I hope the developer has some input, which I would eagerly welcome.