addons.mozilla.org
SwiftTheme is a Firefox browser extension that allows users to apply custom color themes to their browser interface. It offers more than 3 million color options, an intuitive color picker, automatic adaptation to selected colors, multiple theme variants, compatibility with older Firefox designs, and no conflicts with other browser themes. User settings are stored locally on the device and no user data is collected by the extension. A related SwiftDial homepage extension is also available from the developer.