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

简约时尚

Habe Classic Blue und Cassic Black auf dem Firefox 87.0 (64-bit) installiert. Nach dem Neustart des Browsers waren das Blaue bzw. das Schwarze wieder verschwunden.
Es war alles weiß, daraus erfolgte das die Icons des Firefox die inaktiv waren unsichtbar waren.
habe sie sofort wieder entfernt. habe den Vorgang mehrfach wiederholt.

No 21:9 Support (3440x1440)

nice colors and seperations!

I use this theme as my main theme, and it's easy on the eyes while also looking great!

After trying dozens, this is the definitive blue theme that I've been looking for - perfect hue and perfect contrast to several wallpapers I use.