The Lights Off от Codehemu

This extension adds light black layer to all websites including YouTube. That helps protect your eyes a bit. You can control and click on your website while the black layer is on your website. What I mean by this is that even though the layer is on top of your website, you can still control the website over the layer. That way you don't have to close and restart the extension repeatedly.

This will work slightly differently for YouTube. The layer will not affect any video on YouTube, except for this layer, the video will play on YouTube. As a result, you can get more exposure on your YouTube videos.

Selected Features
+ One click on and off
+ Black layout coating on the display.
+ Has no effect on watching YouTube videos.
+ Control over the layer.
+ Very lite and easy to use Extension.