I absolutely love this add-on. BUT BE AWARE! this is not a free plugin. it has a free trial for about a month, but then it goes into lite mode and when that happens, you can only use it with 5 websites. this is a little annoying for me, especially since my school doesn't give a damn about our eyes and won't get their websites to add a night mode. but if I could afford pro, I would definitely get it. 100% recommend from me.