Firefox add-on for night mode. Adds a button on the browser toolbar which toggles night mode on/off. Meaning that backgrounds turn dark gray and most of the text switches to white font color.
Mozilla Addons link: https://addons.mozilla.org/en-US/firefox/addon/nightfoxify/
Chrome version: (see branch chrome_port) https://chrome.google.com/webstore/detail/nightchromed/elknhfpopmgoindibjnlpihgjeibocgg
Github repo: https://github.com/Juz3/nightfoxify
See web-ext documentation for running and buiding: https://extensionworkshop.com/documentation/develop/getting-started-with-web-ext/