29-09-2026 06:30 AM - edited 29-09-2026 09:03 AM
Firefox has evolved significantly over the past year and now, its look has evolved too.
The design begins rolling out today, with Firefox 157, bringing a cleaner, more cohesive , and more adaptable experience. It is still the Firefox you know and trust, with the same commitment to independence, privacy, customization, and user control.
The Mozilla Connect community has helped shape this work from the beginning by sharing feedback on the early designs, tested the experience in Nightly starting in July, filed bugs, and shared with us what worked and what didn’t.
Here’s what landed today.
A cleaner, more cohesive design
The updated design brought bolder color choices to Firefox — and your feedback made clear that opinions on browser color run the full spectrum. In response, we created additional themes, accessible through add-ons and a new theme picker off Firefox Home, so you have greater control over how Firefox looks.
More ways to make Firefox yours
Firefox is becoming more customizable, giving you more ways to shape the browser around how you browse. These options include:
Compact mode now officially supported!
Compact Mode is now available as its own dedicated setting. It will also switch on automatically on smaller screens, reducing the space between interface elements so more fits on the screen.
This is one of the clearest examples of how community feedback shaped Nova. Many of you told us that maintaining a denser interface was important, and we listened.
Faster performance
The refreshed experience also includes improvements to Firefox’s startup, page-loading, and scrolling speeds.
Frequently asked questions
Will my existing themes and add-ons continue to work?
Themes and add-ons should continue to work. Nova is built on the same Firefox foundation, and the extension and theming architecture has not changed.
Will my userChrome.css customizations continue to work?
Some customizations may require minor adjustments, depending on how closely they rely on element names or layout structures from the previous interface.
But keep in mind that Mozilla does not officially support customizations made through userChrome.css. They can cause unexpected behavior or even break Firefox, and future updates may affect them as Firefox continues to evolve. If you choose to use userChrome.css, please proceed carefully.
You can learn more in Firefox advanced customization and configuration options.
Can I opt out of the update?
The new Firefox design becomes the default experience starting with Firefox 157. However, you have several ways to adjust how Firefox looks and feels, including Compact Mode, themes, wallpapers, and New Tab customization.
Keep shaping Firefox with us
Nova may be shipping today, but the work doesn’t stop here. Many of these updates grew directly from the bugs you filed and the conversations you started while the design was being developed.
Update to Firefox 157 to try the refreshed experience, then let us know what works well and what could still be improved. Your feedback will continue to help shape what comes next.
29-09-2026 06:57 AM
"Claude, make our web browser look like the cheapest vibe-coded pile of junk out there.. fix no performance issues. As a matter of fact, make the browser slower but give every edge a rounded corner. Make no mistakes (on the design front)."
Please for the love of god just make a browser that works. Make it look like it's 2002 and make the performance absolutely rip. I DO NOT CARE ABOUT ROUNDED CORNERS ON MY STUPID TABS. I DO NOT CARE ABOUT VAPORWAVE COLORED BORDERS AROUND TABS. STOP PUTTING EFFORT INTO THIS GARBAGE AND JUST BE A WEB BROWSER THAT WORKS. PLEASE!!!!!!!!!!!!!!!
29-09-2026 09:42 AM
I agree that forcing themes down our throats to make developers feel better is trash. If you're going to make themes, they should be optional. I would much rather developers spend their time and effort on performance rather than trying to make stuff look pretty. How much revenue was wasted on color design over performance updates?
29-09-2026 09:50 AM
I know, to think of some of the stuff they could be improving:
Probably more I could think of, but you get the idea: there are definitely areas I wish Mozilla would focus more-on than the look of the browser
29-09-2026 02:28 PM - edited 29-09-2026 02:28 PM
I have to disagree here - Even though I'm of the same mind regarding the redesign as apparently everyone here, I think it's fine to try new things, just don't force it on us as if we were French geese.
Why not add an immediately documented and obvious way to switch back? There already is a "What's new" landing page with lots of available space. Could even combine it with immediate "Feedback" feature (Just ask first and anonymise?). Then they'd know how popular it is - Maybe my opinion is even wrong and the vast majority of users love the new design!
30-09-2026 12:45 AM
I agree that not all UI changes are bad, and even the changes they've made here I could easily just live-with.
But that doesn't change the fact there are clear functionality issues or user-experience improvements that really should be being prioritised over changing the look, introducing new wallpapers or yet more different designs for the "Kit" mascot.
30-09-2026 05:20 PM
I was hoping for a stock matte black theme. i guess i'll download anyone's theme that is truly JUST black. i cannot find any dark theme without bright colors... minimalist can look good too Mozilla!
01-10-2026 04:50 AM
Why is it that I can adjust my 'Theme' but that has zero effect on the look of the tabs?
Themes just adjust the colour of the bar, but not the tabs... It feels like something that should have been changed years ago. Why don't themes get to adjust the look of the tabs?
At the moment, I've moved to Floorp and I won't be updating until I see confirmation that these rounded tabs are toggleable.
29-09-2026 12:21 PM
I totally agree, new UI looks really ugly. Would've switched to another browser if I couldn't revert the UI.
29-09-2026 07:50 PM
Why rounded corners? For 20 years the browser had rectangle - no need to change it. If you want options add options I do not want rounded tabs - waste of time of developers. Wrong, change it back or give options. With these changes Firefox makes it harder and harder to use it. You are chasing new users who wont come but pushing long time user away.
30-09-2026 06:01 PM
How did you fix it I need that right now please.
01-10-2026 01:03 AM
In the address bar, type about:config , then press ENTER
Accept any warning
Search for nova
Double-click on "browser.nova.enabled" to change it to "false"
01-10-2026 04:51 AM
This needs to be at the top of the forum post.
01-10-2026 03:49 AM - edited 01-10-2026 03:49 AM
Can people here not see any-other replies or something? This is being asked like 4-5 times an hour at this point! 🙃
Anyway:
Type about:config in the address bar, then press ENTER
Accept any warning shown
Search for nova
Double-click the line "browser.nova.enabled" to set it to "false"
01-10-2026 01:00 AM
How did you revert the ui? its so ugly
01-10-2026 01:02 AM
Type about:config in the web-address bar, then press ENTER
Accept any warning shown
Search for nova
Double-click the line "browser.nova.enabled" to set it to "false"
30-09-2026 03:06 AM - edited 30-09-2026 03:27 AM
30-09-2026 05:01 AM
i fully second this notion
30-09-2026 04:31 PM
Agree... this change was not needed.
29-09-2026 07:33 AM
I don't like this rounded corner design. It looks very uncomfortable and awkward. I hope the square tab design can be changed back, or at least allow us to choose.
29-09-2026 10:56 AM
Web-address bar -> about:config -> ENTER -> search for nova -> double-click the line "browser.nova.enabled" -> "true" should change to "false"
UI should get reverted, until a future Firefox update removes that setting, or stops it working
29-09-2026 01:06 PM
Thank you so much! I also turned off auto updates.
30-09-2026 12:53 AM
I wouldn't recommend turning-off the updates, as there could be a security issue then that you won't get patched for.
You'd be better off downloading the "ESR" version of Firefox from https://www.firefox.com/download/all/desktop-esr/ , uninstalling your current Firefox v157.0, restart your PC, then install the ESR version. Then you'll still get security-fixes, but you won't get the new UI for around a year.
Might be worth backing-up your passwords, bookmarks and history before doing this, just in case: Menu > Settings > Account and Synchronisation > Turn on backup (unless you're already using it). Then if your stuff is missing after you first start the ESR version, go back to that screen and use the "Restore your data" option to bring it back in
30-09-2026 04:22 AM
I wish they had two branches: one for their design crap and one for security and you can subscribe to either.
The way now you either get their design crap trojan horsed with security or you reject it all and go naked security wise.
30-09-2026 04:27 AM
Technically, they do: "beta" (one version ahead), "developer edition" (two versions ahead) and "nightly" (the most aggressively up-to-date) is where they test stuff.
Once they get feedback from those versions and something seems okay, it then makes it into the stable release. The ESR versions are for those who want change less-often.
30-09-2026 12:35 PM
Well, the dev and beta tester feedback is NOT WORKING. They just rolled out a UI update that made my browser trick me into believing I was having a nightmare where I was trapped in the new Barbie movie.
30-09-2026 12:10 PM
Well last couple of updates made FF much worse. It's unstable, slow, ugly. I use this browser for more than 20 years and I really struggle to remember when it was this bad. So no, I'm not worried about missing security updates. I'm more afraid that an update will make it even worse. Looks like AI has taken over the development... at least I hope it's the AI's fault.
I thank you for the info about config flag. That helped a little.
30-09-2026 12:38 PM
If AI did this, it was hallucinating.
Even the AI slop normally doesn't get this bad.
If actual people did this...well, same thing.
Don't do drugs, kids. Drugs are bad.
30-09-2026 06:03 PM
I don't care how bad the security fix is if they are gonna do this rounded stuff I'll just not update.
29-09-2026 03:49 PM
Thanks a lot! That was an eye-saver!
29-09-2026 07:52 PM - edited 29-09-2026 07:53 PM
Why should users hack their own browser, profiles, power users use more than one profile and hack each of them to make Firefox regular again? Such option must be in UI and change optional. not this. This is wrong.
30-09-2026 12:56 AM
I agree, but it's unlikely Firefox will revert the new UI so you have two choices:
1. Make the change I suggested in about:config
2. Download the latest 153.4.0 "ESR" release of Firefox, uninstall your current 157.0, restart your PC, then install the ESR version. Then you won't have the new UI for around a year from now, until you get moved to a newer ESR. Clearly that is more work though, and probably best to use the "Backup" option in Menu > Settings > Account and Synchronisation before removing 157.0 to ensure you don't lose anything in the move!
30-09-2026 06:43 PM
I would add a 3rd option to that list: switch to Vivaldi!
I did, and it is AWESOME. No more bubble tabs, no more psychedelic gradients, no more weird UI stuff...I set my appearance to rectangles only (no rounded corners at all), and straight black/white/gray color palette. It looks and functions exactly like a browser should - unobtrusive, invisible, just sitting there in the background serving up webpages like it's supposed to.
30-09-2026 12:10 AM
Not all heroes wear capes my guy. I hope you stub your toe on a winning lottery ticket or a gold bar or something. Stay frosty mate ❤️
30-09-2026 12:29 AM
Thank you so much. The design still looks awful (I think an UI UX school dropout designed it) but at least now the ridiculous rounding is more tolerable.
30-09-2026 02:06 AM
You absolute legend. Actually looks a Firefox browser again after following your suggestion!
30-09-2026 07:12 AM - edited 30-09-2026 07:19 AM
Thaaaannnnnk !!!! from my eyes 😎
That was an undesired round update 😱 😩😡
Compact is nice 👍
Old logos are nices 👍 but need to apply everywere 👎
No to round stuff everywere 👎
No to default theme, 👎 I just want the colors I already choose in Windows
And stop with purple go back to blue and orange plz
30-09-2026 01:39 PM
fantastic. thank you
30-09-2026 02:27 PM
TY legend
30-09-2026 04:37 PM
dude thanks for putting this out there.... i need the new changed sucked but didn't realize just how blurry it made all the icons and such until i clicked between disabled and enable.
how can they say they improved the UI when in fact making things more blurry?