FireThemes by Psicora

FireThemes lets you change the look of Firefox directly from the sidebar.
- Style Library: professional dark and light themes, gradients, animated styles, and eccentric designs.
- Color Studio: customize the background, toolbar, accents, and text; create two- or three-color gradients with an adjustable angle.
- Color Animations: scrolling, breathing, pulsing, flames, rainbows, and more, with adjustable speed. No stroboscopic effects.
- Readability Check: shows whether the contrast between text and background is sufficient.
- Day/Night Automation: choose two styles and set the times for switching between them.
- Save Your Styles: save your styles and export or import them via the clipboard.
No data is collected or transmitted: the extension does not use the network and stores settings only in your browser.