On GNOME, Unity, Cinnamon, MATE, Xfce, LXDE and all other GTK+ based desktop environments choose a deep-dark theme such as Dorian. If you already run GTK+ 3.20 check out Cloak 3.20 or the darkest variant of Candra 3.20.
These are full-featured themes by killhellokitty that include modifications for Google Chrome (Chromium), Firefox and Thunderbird.
Install Stylish on your browser and search userstyles.org for dark themes for you favourite websites. Here is a set of theme that might be useful:
- Dark Wikipedia Rounded
- GitHub Dark
- Stackoverflow Dark
- Quora Dark
- Jenkins
- Darker Google
- Discogs Dark Ultimate
- Black Youtube by Panos Soundcloud.com - Nightmode
- Userstyles Deep Dark Wide
You should also get Global dark style - changes everything to DARK and enable it whenever there is no custom theme for the website you are visiting.
Meld visual diff tool
Save gtk.css into ~/.config/gtk-3.0/.
Use geany-themes.
UI: Window > Preferences > General > Appearance enable theming and select the dark theme.
Syntax colouring: Install Eclipse Color Themes, go to Window > Preferences > General > Appearance > Color Theme and select a dark theme.