not well fit
to wide screen

That's theme so good

The latest version of FF(96.0.2) goggle and bookmark background turns black

The latest version of FF(96.0.1) goggle and duckduckgo background turns black.

Love the blue gradient with the soft gray.

the best

Best Theme in Firefox

Clean and pleasant (should be called Troposphere or something as it reflects the beautiful silverwhite-blue skies here in the NW) and readable except for miniature icons - I find any design or ornamentation just compounds the complete absence of tab definition.
I feel like a Tab Hunter (that's a joke, kids.) This smooth neutral grey background does have the best chance of rendering most intentionally eye-catchingly colorful icons — except (ahem!) for Apple's logo, which practically vanishes on my screen. What's with their eschewing of color?
Do I have control of any of these aspects? I can't find any.
IDEALLY the sizing of icons and their spaces would be dynamically sized with additions and removals – as I assume your (invisible) tabs and the OS Dock are.
Keep up the good work