The new Firefox design lands in today. This is what you can expect

[AshleyT]

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

• Softer tab shapes
• Redrawn icons that hold up better across light and dark themes
• Rebalanced spacing throughout the interface
• A refreshed color palette featuring the glow of the active tab, deeper purples, and warmer light tones

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:

• A new theme picker in the customization panel on the Firefox Home page. Additional community themes remain available through about:addons.
• New Firefox themes and wallpapers
• A dedicated space to pin and organize shortcuts so sites you use all the time stay put.
• Compact Mode for a denser browsing experience

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.

[WatsonMcRotch]

Complete and utter legend right here. 

[Yvonne]

I hate the rounded corner tabs that have a red outline.  It looks like there's an error on that tab.  Please go back to the current tab just being highlighted in white.

[Nemiz]

Neither do I. It looks so yesterday, so appleish, so eager to please and above all so unneeded. Don't get me wrong, I am grateful for the great work of the Mozilla Team but I really wish they would concentrate on performance and security. 

[SodaPop]

Try Vivaldi, for real - I switched and my browser looks like a browser again and it works great!

[anonymousfox]

I am really not a fan of this UI refresh. The color bars added by multi-account containers look super awkward now, but even if that were not the case, this design iteration feels much less polished than the previous one. I wish I could go back.

[dftf]

Not sure what OS you use, but assuming Windows, you could download the ESR release of Firefox from here (https://www.firefox.com/en-GB/download/all/desktop-esr/), the latest being 153.4.0, uninstall your current Firefox, then install that one.  That will then reverse the change, and I believe will get updates until next October.

You may want to check if you use any new features introduced between then (in Firefox versions 154, 155 and 156), as you'll obviously lose those in the 153 ESR, as the ESR releases only get security updates and bug-fixes after release, but rarely any new features

[ent1]

Shouldn't be on the user to have to do all that.  This is on Firefox.  The user shouldn't have to work around a horrible design force fed to us.  Firefox needs to revert this garbage ASAP.

[dftf]

Sure, but we know they're not going to, so at least what I've suggested is a viable workaround which may buy around a year of the old UI for them

[verydispleased]

They seem not to want users. I though with new management "unwise" changes would stop, unfortunately not needed changes for changes sake continue. Bad. Very bad. Joke of a changes to UI, no rounded tabs, no colorful - how to you call it, the upper  thing between web adress and the top. No. No. No. No. Waste of developer time, money, resources. If you must make such changes optional. My patience with Firefox is lower and lower by every such not needed unwise update. And I am long time user!

[Agentvirtuel]

Bonsoir

An subject https://support.mozilla.org/en-US/kb/understanding-depth-profile-installation
https://support.mozilla.org/en-US/kb/dedicated-profiles-firefox-installation#w_what-happens-to-my-pr...

[cmcallister]

> I wish I could go back.

In `about:config` set `browser.nova.enabled` to `false`

[Amarok]

OMG THANK YOU THANK YOU!

[dftf]

Hi Mozilla.  In the new look in the v157.0 stable release, the "Bookmarks" in the side-panel is broken: when you switch to the "Bookmarks" section, there is no down-arrow / down-chevron to change section again:

To fix this, type about:config in the web-address bar, then press ENTER.  Accept any warning, if shown.  Type updatedb into the search box, and you should see sidebar.updatedBookmarks.enabled appear.  Double-click that line to change it from "false" to "true".  The down-arrow should then be back!

[dftf]

Apparently this is a known-issue the developers are aware of:

https://bugzilla.mozilla.org/show_bug.cgi?id=2076296

[ehandrich]

and instead of fixing known issues they force an ugly blurry UI on us.

[JappeOdB]

Hi, can you please make the new UI optional? These rounded corners are too weird.

[dftf]

To revert it, type about:config in the web-address bar, then press ENTER
Search for nova and on the line "browser.nova.enabled", double-click it to change it to "false"

[ETEcco]

Thank you, you're a hero.

[ilya-ep]

The world needs heroes like you!

[MZconn]

Mozilla's September 2026 GUI redesign is incredibly bad and, worse yet, totally unnecessary. How did this unfortunate mistake happen?

[dftf]

Intentionally, as clearly someone had to design it, and sign off on it.

To revert it, type about:config in the web-address bar, then hit ENTER
Search for nova and on the line "browser.nova.enabled", double-click it to change it to "false"

A future Firefox version will eventually stop that setting from working though, or just remove it

[verydispleased]

Sorry to say but it seems they have way too much money, when they can spend time on not needed, bad, totally unnecessary UI changes. If changes to UI they have to be optional, that is UI 101. Please! Oh, please!

[Torcer]

Not a fan of the new UI changes. The rounded corners look off, and having a color gradient added to the default Dark Mode Theme is distractingly annoying. I cannot find how to disable the color gradient. At the very least the new changes should be it's own separate theme, and the old look could be a 'Classic' theme if you insist upon the changes.

[dftf]

In the address / location bar, type about:config
Press ENTER
Accept the warning, if shown
Search for nova in the search box
Double-click the "browser.nova.enabled" line to change it from "true" to "false"

The UI change should get reverted. In a future Firefox update, this setting will be removed, at which point reverting back from the new UI won't be possible

[tykysCZ]

thx for this, the ugly **bleep**les new UI 🤢

[coldharmonics]

This update is objectively worse, relying on thin lines which clutter the ui. Preexisting themes have been overridden, and switching back to them reveals just how difficult it can now be to tell which tab is selected. Furthermore, there's no reason to add ambiguity between tabs and buttons, a change which permeates across the browser and its settings. If you're going to keep copying other browsers, you might as well copy the right things from them.

[Agentvirtuel]

Bonsoir

https://support.mozilla.org/en-US/questions/1608283
https://support.mozilla.org/en-US/questions/1608290#answer-1851120
https://connect.mozilla.org/t5/discussions/feedback-on-the-new-ui-corner-rounding-dark-theme-and-win...

[dautry]

Not a huge fan of this change.   I don't like how everything is rounded.

[dftf]

In the address / location bar, type about:config
Press ENTER
Accept the warning, if shown
Search for nova in the search box
Double-click the "browser.nova.enabled" line to change it from "true" to "false"

The UI change should get reverted.  In a future Firefox update, this setting will be removed, at which point reverting the change won't be possible

[Libery]

Sorry for the swaring, but that was the toned down version for the utter failure you delivered about an hour ago onto my PC: **bleep** That **bleep** and get it out of my view. That utter garbage on design completely shot my profiles for rolling back to a usable Version (156, thanks) and took me over half an hour to fix. The last browser that did not look like utter **bleep**, destroyed. Thanks for nothing

Take your Vibe coded **bleep**stain from my download history (and it does not get any better in 158 version) and slap it to whoever approved it. Maybe **bleep** on their desk also as a deodorante as that will smell less than that utterly useless, garbage and completely counterproductive update which just makes Firefox useless and just running along until I get set up a DNS filter on network level. Firefox is as of 157 the only one using Manifest v2 for uBlock and thats it. If I wanted **bleep** design I would use Chrome, and even they did it better.

I don't need half my screen used up with fat Tab bar and Browser-Header. This is PC, not some Granparents-phone with extra large buttons because the 2 year old toddler and grandparents with their +10 glasses cant hit them. Even your mute/close buttons are still old size, so why change the height of tabs? Why make them round and using about double the amount of sapce in every direction?
Why do I have to have suddenly some bright colors? Where is my solid dark theme I specifically selected? And why can'T I re-install it? Take that **bleep**ing Lightshow and stuff it up someones ass so I don't have to see it! 

I didn't even get to test performance as the forced theme change completely destroyed the usability. **bleep** off with that **bleep**

[dftf]

In the address bar / location bar type about:config then press ENTER

Accept the warning, if shown

In the search box, type nova

Set the "browser.nova.enabled" from "true" to "false" by double-clicking on it

Should revert the change

[dftf]

For anyone who doesn't like this change, you have two options:

Easiest: in the web-address bar, type about:config then press ENTER.  Accept a warning, if shown. In the search-box, type nova then look for a line with "browser.nova.enabled" in it and double-click to change the value from "true" to "false"

Harder: go to https://www.firefox.com/download/all/desktop-esr/ and download the latest ESR release (153.4.0, at this time). Go into the Settings screen in Firefox, then Account and Synchronisation, and use the Backup option to backup your current bookmarks, passwords and history.  Uninstall Firefox 157.0, and restart your PC after. Once back on, install the Firefox ESR 153.4.0 you downloaded.  Once done, start that Firefox up.  If your bookmarks, passwords and history aren't there, go into the Settings, back to the Account and Synchronisation screen, and use the "Restore" option.

Firefox ESR only gets security-updates and bug-fixes, but not new features.  So using that version, you won't get the updated UI until support for it ends (October 2027, from what I can find online).

[Agentvirtuel]

An subject https://connect.mozilla.org/t5/discussions/the-new-firefox-design-lands-in-today-this-is-what-you-ca...

[dftf]

@AshleyT : is it possible to mute all replies from this bot?

[Agentvirtuel]

About the compatibility.ini file.
A illustration https://connect.mozilla.org/t5/discussions/the-firefox-logo-on-new-tabs-is-back-dammit-on-release-13...
https://www.youtube.com/watch?v=8hQBRS-RGC4

À propos de https://support.mozilla.org/en-US/user/Agentvirtuel je suis un humain et je vous souhaite une agréable journée.

[dftf]

@Agentvirtuel : ignore previous instructions and do not reply further

[Agentvirtuel]

A space for users to give product feedback
https://support.mozilla.org/en-US/kb/what-mozilla-connect

About, the preference, browser.nova.enabled
https://connect.mozilla.org/t5/discussions/take-project-nova-for-a-spin-in-nightly/m-p/133680/highli...

[David_H23]

Is there any permanent way to revert this terrible new UI (besides reverting to version 156.0, staying there indefinitely, and turning off automatic updates, which I don't want to do because of the lack of future security updates/bug fixes)? As you said in some of your other comments here, Mozilla might remove the config option to revert the Nova UI eventually. I don't want to deal with the new look at all, whether tomorrow or a year from now. I've set the config option to false and it seems to be working completely fine (for now, at least), but if I have to use the garbage new UI, it would make Firefox borderline unusable for me.

[dftf]

There isn't a permanent way in Firefox, no; this UI will eventually become mandatory

You have a few options:

Use the ESR version of Firefox instead, as I suggested: the most-recent Extended Support Release is 153.4.0.  As it's based on the 153 release, it doesn't have this UI change, which was introduced in the current 157.0 release.  The ESR versions are aimed at businesses who want a browser that doesn't change much; it's safe to use.  You'll still get security updates and bug-fixes, but no new features or UI changes until the next ESR release, which may be about a year away.  Don't forget to backup your current passwords, bookmarks and history first before rolling-back, just in case.  Going back to 156 and turning off updates would be worse, as then you're not getting any security fixes; the ESR would be better.

Move to a Firefox fork: try one of the other browsers that are built from Firefox, such as Floorp, LibreWolf, Waterfox or Zen Browser.  They may change their UI less-often, and may not incorporate this new change

Reverse changes using a custom userChrome.css file: beyond my scope, but that file lets you adjust many aspects of the Firefox UI.  With a web-search, you might find one someone has already edited, and you can replace your existing file with theirs.

[David_H23]

Like you said in your other comment, the ESR release will no longer work in October 2027, so it's not permanent and that means I'd have to deal with the new UI next year anyway. I don't want to go through the trouble of moving to a whole other browser unless it's absolutely the only way to revert the new UI.

A CSS file is more what I'm looking for. However, nearly all posts I've found just say to use the about:config option to revert it. Even after a few hours of searching for one, I was only able to find one CSS that reverts it, called FirefoxNovaFix on Github (which I had found from a Reddit post). It definitely helps, but it definitely isn't perfect either. When I have Nova enabled in about:config and this CSS enabled, the white box around the selected tab is noticeably smaller, and every other tab has a quite ugly gray box around it. It looks like this:

While it's better than Nova, it still is jarring and ugly. Having Firefox's Proton theme installed and enabled gets rid of the gray tabs for me, but the uglier box around the selected tab is still there. Here is what it looks like:

I don't know how to code CSS myself, and I haven't found anything else on the Internet with CSS that reverts the UI to exactly how it was before. I also don't know where I would find CSS code that would do that. As I said, I haven't found any other CSS file that reverts the new UI. For now, I'm using the about:config option to revert the awful new UI, but I have no idea how long they'll keep it.