Great but if you switch Windows 10/11 themes colors to the dark, the effect will be the same with original Firefox Alpenglow theme.

Overall it's excellent.

Pros:
- The white text on the dark background in the toolbar is clear, unlike other themes.
- The border around the current tab provides a clear visual indicator

The developer has created and excellent UX.

Cons:

The background colour when text in the url bar is selected is far too subtle.

Nice Colors

sipp