=Using custom css via a browser extension=
[[File:stylus.png|thumb|Dark theme 2 as discovered by [https://add0n.com/stylus.html Stylus] extension. Once, discovered, clicking on the screenshot will install it]]
You can drop the following code in [https://add0n.com/stylus.html Stylus] (an extension for Chrome, Firefox or Opera and you can also [https://github.com/openstyles/stylus/issues/19 install it], as well as any other Chrome extension, on Edge browser) or any other styling extension (or access it directly from [https://userstyles.org/styles/185826/lsj-gr-dark here] via an extension), and have lsj.gr displayed in a dark theme. It is also discoverable via Stylus and other extensions when you visit lsj.gr, click on the extension icon and then click '''Find styles''' and when the style is found, clicking on it will install it (mind you, the userstyles.org site is often unresponsive with 504 Gateway Time-out errors, so you may not get results there). This code works for wikipedia sites as well. You can simply add the extra URLs it should apply to via the extension settings (just use '''wikipedia.org''' in the '''Applies to URLs on the domain option''' in Stylus). '''Dark theme 2''' is specifically written for '''Timeless''' Mediawiki theme, so you get good results if you have changed your Wikipedia user settings to '''Timeless'''.
As you can see, there are 2 dark theme styles to choose from. '''Dark theme 1''' is simpler and '''Dark theme 2''' more elaborate.