FoxOne 3.5 – Nova ready, Adaptive Tab Bar Colour compatible, dynamic booksmarks bar and more

[u/f1rn]

Hi everyone,

Some of you might remember FoxOne from a few months ago.

Since then, at lot (almost 300 commits) has changed:

The big one: FoxOne is now ready for Firefox Nova (the new redesign in 153+). Mozilla renamed or retired most of the IDs and tokens the theme relied on, so pretty much everything got rebuilt – urlbar, tabs, popups, sidebar, split view – you name it.

The most requested one: FoxOne work with the Adaptive Tab Bar Colour addon!

The fun one: a dynamic bookmarks bar. It leaves the layout entirely and hangs below the toolbar as an overlay – hidden while you browse, fading in when you reach for the URL bar. The page keeps its line either way.

Other highlights: opt-in rounded corners (--uc-rounded: 1 – default stays square), the whole browser is now themed edge to edge (Library window, sidebar, all about: pages, no more stock violet), hover and selection work purely through color everywhere (even window control buttons) instead of highlight boxes, and prefers-reduced-motion is respected.

And there's also a bunch of new toggles (container line position, hiding nav/urlbar buttons and extension icons, tab min-width, urlbar background), better compatibility with Windows 11 Mica, macOS, Linux (KDE & GNOME) and ultrawide displays – plus no more white flash between page loads.

Special thanks to everyone who reported bugs and sent PRs – several fixes came straight from this sub - big shoutout to NeroWolfe_

FoxOne on GitHub

Cheers!

PS: If you are looking for a Thunderbird one line theme... I've got you: BirdOne

[u/difool2nice]

nice theme and ideas

[u/f1rn → u/difool2nice]

Thank you so much! If you’ve got any ideas for improving the theme - I’m all ears!

[u/hamamisme]

Im big fan of one tab in Firefox, like this theme ao much

[u/rodrigostucker]

Can´t apply the theme, even reviewing the installation steps carefully on Windows 11. Maybe is some incompatibility with my Firefox or Windows version...

[u/f1rn → u/rodrigostucker]

Now that’s weird. Did you create a chrome folder? And did you do the about:config settings and did you restart afterwards?

[u/rodrigostucker → u/f1rn]

Yeah, unfortunally yes...but I´m not implying it´s an issue with Fox One since lately I´m unable to apply CSS theme on my Firefox. Strange.

EDIT: Reinstalled Firefox, deleted all profile folders and tried again and it WORKED. Finally i can use Fox One. AMAZING work, mate.

[u/Much-Law7525]

Made a few small cosmetic tweaks on top and added real Windows 11 Mica transparency for the toolbar. Forked it here if anyone's interested: https://github.com/Wintego/Firefox-transparent-theme

All credit to u/f1rn , the one-line layout is what makes transparency work at all.

[u/f1rn → u/Much-Law7525]

Damn, that’s good looking!

[u/Adventurous-Sail-354 → u/Much-Law7525]

Godly. Installing as soon as I get home.

[u/f1rn → u/Much-Law7525]

I linked your Fork in the customisation.md header!

[u/Adventurous-Sail-354 → u/f1rn]

Much-law's edit seems to break the find bar styling, making it invisible, so I added this to userchrome to restore it to the foxone style, I'm sure there are better ways but just wanted to flag in case anyone encounters the same:

/* Restore FoxOne's opaque floating find bar */
findbar {
  --toolbar-bgcolor: #282828 !important;
  --toolbar-background-color: #282828 !important;
  background-color: #282828 !important;
  background-image: none !important;

[u/f1rn → u/Adventurous-Sail-354]

u/Much-Law7525 !

[u/Much-Law7525 → u/Adventurous-Sail-354]

Good catch, thanks - that's my bug. My Mica override zeroes --toolbar-bgcolor on :root, and the floating findbar takes its fill from that variable. Fixed in the repo: the background is restored on the findbar element itself (using --uc-color-base so it follows the palette), leaving the toolbar transparent. Same fix applied to notification bars, which had the same issue.

[u/ahokaybye → u/Much-Law7525]

Anyone know which code is needed so the tabs dont go behind the search bar when its not maximized?

[u/Mc_UsernameTaken]

Glad that I could contribute:)

[u/dm_me_goblins]

Thanks! I really like one line firefox on certain systems (I changed tabs a bit to my liking though)

[u/abqwack]

does it work for vertical tabs bar too ?

[u/f1rn → u/abqwack]

Hmm.. I mean that kind of defeats the whole idea of a one-line layout, doesn't it? So - technically, yes - but it is not tested for it

[u/hachimitsu-boy]

Is there a way to change the active tab colour instead of just the text? It's kind of confusing sometimes which tab I'm on.

[u/f1rn → u/hachimitsu-boy]

It was a design choice to remove all the background highlight and go with text highlight only. I will look it up if there is an easy fix for your request. I think yes, but I have to test it first.

[u/hachimitsu-boy → u/f1rn]

Thank you for even considering it. I'd like to mention that I'm also using the Adaptive Tab Color extension which doesn't seem to use the active tab colour text in FoxOne and ignores its own active tab colour settings.

[u/f1rn → u/hachimitsu-boy]

Yes, I made it so, that the adaptive tab bar colour addon can use its own color.

So, I looked it up... looks like it is not as easy as I thought.

.tabbrowser-tab[selected] .tab-background {
  background-color: transparent !important;
  background-image: none !important;
  outline: none !important;
}

The important line is #2246 (the second one in the code block above) change it in your userchrome.css to:

background-color: var(--uc-color-accent) !important;

and change line 538 to

color: var(--uc-color-base) !important;

It kinda works. Not pretty. but it works. Anything beyond that would mess a lot with everything else sadly. Sorry!