Twitter's mobile app for Android and iOS has a night mode which has a dark theme. It is not available for the twitter web app yet. This add-on brings the night mode to web. Night mode is enabled by default and it can be switched to the default theme by clicking on the twitter icon that shows up in the address bar when you visit twitter.com. It currently applies the theme only to the Home tab / timeline. If you would like to have this applied to other pages too, please let me know in comments here or on Github link given below. Of course, would appreciate any donation - https://www.paypal.me/tsriram :-) This add-on does not access your personal data. I wrote about it here - http://tsriram.in/2016/08/24/bringing-twitter-night-mode-to-web/ Please feel free to report issues and share feedback here - https://github.com/tsriram/twitter-web-night-mode/issues