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.

[grk373]

PLEASE unsoften the tab shapes, unredraw the icons, unrebalance the spacing, and unrefresh the color palette!!!!! Just because you can doesn't mean you should!!!!

[dftf]

If you haven't already, follow these steps to undo most of the recent change:

URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

Then you can go here to install the previous theme:

https://addons.mozilla.org/firefox/addon/firefox-proton/ 

[TxF]

The Firefox 157 theme refresh was terrible. I updated and found my browser painted in gradients I never chose, with no way to get back the clean System theme that simply followed Windows dark mode. Every built-in option, including Default and Dark, now carries the same gradient, so "switching back" isn't possible. I had to dig through add-on listings to find a separate Proton theme just to get my browser back to how it looked last week.

I've stayed with Firefox for years out of loyalty I can barely justify anymore, and this change has nearly used up what's left.

[AstrobotNautics]

Try Floorp or Waterfox, they are generally a bit more stable when it comes to design choices. Waterfox still implemented Nova, but it's much easier to turn off. Floorp has just disabled it outright for as long as Photon or Proton are supported, also it comes with Red Pandas. 

[FvckGenAI]

This is the ugliest you have ever made the browser.

Literally making it look like every vibe coded "app". Is the plan to lose users?

[dftf]

To reverse most of the recent change:
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

The previous theme is available here:
https://addons.mozilla.org/firefox/addon/firefox-proton/

⚠ The ability to reverse Nova may end in Firefox v161, expected Nov 24, 2026
See: https://bugzilla.mozilla.org/show_bug.cgi?id=2071454

[Thristam]

so nova will be mandatory for v161 ?...... ( !!!!! ). If so, i must block updates before the Nov 24, 2026.... ( great for the security !!!!!... ).  Thank a lot for the information. And good luck ... 

[dftf]

Rather than block updates, move to the 153.4.0 "ESR" version of Firefox:
https://www.firefox.com/download/all/desktop-esr/

As it is based on version 153, it predates the new UI in 157.  The ESR versions get security-updates for about a year, but no new features or UI changes, so you'll be safe but avoid the new UI.

You'll need to backup your current data (bookmarks, passwords, history, etc) first:
Menu -> Settings -> Accounts and Synchronisation -> Backup

Then uninstall 157, reboot your PC, then install the 153.4.0 ESR.

If your find your data isn't there, simply restore it from the backup you did earlier:
Menu -> Settings -> Accounts and Synchronisation -> Restore your data

[Dippy2]

The new icon styles are just horribly inaccessible. They've become rounded and blobby, which makes them harder to tell apart. And the colors on things like container selection icons are now outlines, not filled in, so there's little color to assist with telling them apart. (Not helped by the new color pallet, but I imagine that part can be changed with themes.)

And +1 to everyone who says it's ugly.

Many thanks to the other users for suggesting ways to undo this interface change. 

[rw335i]

I hate the weird colors and the menu(?) on the sidebar which keeps my Show Sidebars icon from working properly. Some of the top headings are now almost unreadable. Luckily I found out about the sidebar.revamp  & browser.nova.enabled flags. Please concentrate on what is important rather than on pretty colors. And DO NOT remove these flags.

[Thristam]

What is the **bleep** with theses **bleep** around corner tabs ?????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! And for a macOs look ???!!!!!!!!!!!!!.... More firefox customization and i can't get rid this **bleep** !!!!!!!

I hope i can easyly by userChrome.css ...... ( and forever !!!!!!!!!!!!!!!!!! ). Else i must go back to 156 version and block the updates!!!!! ( cool !!!!!!... ). And after 1 year of no updates i must leave firefox after at least 20 years of using !!!!!!! THANK YOU !!!!!!!!!!!!!!!!!!!! 

[AstrobotNautics]

See dftf's replies further up, or this thread here:
https://connect.mozilla.org/t5/discussions/bring-back-rectangular-tabs/m-p/140846#M57393

This disables it without add-ons. 

URL= about:config, search for nova, set "browser.nova.enabled" double-click to "false"

Try Floorp or Waterfox as alternatives, they are generally a bit more stable when it comes to design choices. Waterfox still implemented Nova, but it's much easier to turn off. Floorp has just disabled it outright for as long as Photon or Proton are supported, also it comes with Red Pandas.

[Demetry]

Almost all of my tabs with youtube videos are now about:blank but still show the title of the video in the tab... whatever you have done: its a fail.

And nobody asked for rounded tav edges. It looks just cheap and hurt my eyes.

Stop doing such nonsense every x years. If someone want a new design, they can install a theme.

Thank you for your attention and have a nice day

[dftf]

1. Undo most of the new UI changes by:
Typing about:config then pressing ENTER
Accept any warning shown
Search for nova
Double-click on "browser.nova.enabled" to set it to "false"

2. Install the previous "Proton" theme from here:
https://addons.mozilla.org/firefox/addon/firefox-proton/ 

3. For your YouTube issue, you likely use the "Ghostery" ad-blocker, and that is causing the broken YouTube.  Either disable it on YouTube, or check for updates for it, and it's hopefully now sorted.  There were literally like 40-50 reports on Reddit of people all saying Ghostery had broke YouTube for them

[zombieman]

I wish this "Nova" thing was more about undoing to changes that the Proton UI implemented. Didn't like Photon either or even Australis before that if I'm honest. "Softer tab shapes" is absolutely NOT want I want. I want hard edges even between inactive tabs. I want CLARITY on where tabs are and ideally tabs to be below the address bar and can we put an end to this thing about getting rid of menu and title bars. I *ALWAYS* turn those back on with EVERY install of Firefox. Those are the best UI feature of Firefox over Chromium browsers.... Oh and I'd quite like a proper preferences window back please... And a downloads window...

[AstrobotNautics]

I do find it strange that 'themes and customisation' doesn't give options to alter tab styles. It alters the background colour, but why hasn't 'appearance' also allowed you to customise tab shapes through the years...
Waterfox gives you options, but it is only between Nova, Photon and Proton, so I think you're a bit out of luck there. 

[NoName1231]

It's horrible and I was not asking for it. At least give an option with square tabs. The grey one without gradient is alright but the round tabs still annoy me so much, I consider changing the browser altogether. 

[AstrobotNautics]

Try Floorp or Waterfox as alternatives, they are generally a bit more stable when it comes to design choices. Waterfox still implemented Nova, but it's much easier to turn off. Floorp has just disabled it outright for as long as Photon or Proton are supported, also it comes with Red Pandas.

[dftf]

1. You can undo most of the new UI changes by:
Typing about:config then pressing ENTER
Accept any warning shown
Search for nova
Double-click on "browser.nova.enabled" to set it to "false"

2. Install the previous "Proton" theme from here:
https://addons.mozilla.org/firefox/addon/firefox-proton/ 

3. Look into Firefox alternatives, such as "Floorp", "Librefox" or "Waterfox".  Some will also have adopted the new "nova" UI, but allow for easier reversing of it

[mlwasteland]

Can you make a less sensitive skin for those that appreciate efficiency and fewer wasted pixels? Something more pragmatic? Or, would that offend too few people?  

[dftf]

1. Undo most of the new UI changes by:
In the URL bar, type about:config then press ENTER
Accept any warning shown
Search for nova
Double-click "browser.nova.enabled" to set it to "false"

2. Install the previous "Proton" theme from here:
https://addons.mozilla.org/firefox/addon/firefox-proton/ 

3. Or explore other themes here:
https://addons.mozilla.org/firefox/themes/ 

[NoName1231]

Thanks, but if I have to put in any effort, it's shifting my bookmarks to another browser...

[dftf]

You're free to move to a different browser any time, of course.

Though that will likely take more-time than the 30 seconds at-most to make those changes, so maybe try them first?

[F_firefox]

It's fugly. I've stuck with Firefox through a bunch of BS, but making it visually hideous on top of the AI bull**bleep** and data collection by default? F right off; F Firefox.

[dftf]

If you haven't already, you can undo most of the new changes by:

Typing about:config in the URL bar, then pressing ENTER
Accept any warning shown
Search for nova
Double-click "browser.nova.enabled" to set it to "false"

[Gonzo-Goliath]

How can I undo all the UI design changes from the last update? It looks absolutely rubbish now with those jagged tabs and menus!!! I’m not going to spend 100 hours on custom CSS just to get the previous interface back!

[Gonzo-Goliath]

How can I undo all the UI design changes from the last update? It looks absolutely rubbish now with those rounded tabs and menus!!! I’m not going to spend 100 hours on custom CSS just to get the previous interface back.

[dftf]

In the URL bar, type about:config then press ENTER
Accept any warning shown
Search for nova
Double-click "browser.nova.enabled" to set it to "false"

That will undo most of the changes

[Gonzo-Goliath]

Thank you very much, the old user interface is much clearer and more minimalist. 😍

[Elfener]

Is this why my browser chrome looks like those AI slop websites rather than my system theme like it used to?

Who decided this was a good idea?

[dftf]

To mostly-undo the recent change:

URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change it to "false"

You can install the previous theme from here:

https://addons.mozilla.org/firefox/addon/firefox-proton/ 

[ZCi2Fuxr3Hvj]

The containers tabs are hard to use now, I tried all combinations of available colors and even after setting a theme with high contract background between 4 containers you can't avoid having 2 confusingly close on a regular cheap lcd laptop screen. Don't like the esthetic part either but whatever.

[dftf]

These steps will mostly-undo the recent change:

URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change it to "false"

And you can get the previous themes here:

https://addons.mozilla.org/firefox/addon/firefox-proton/ 

[HstsLover]

PLEASE stop changing the design, not only is it pointless but opening your browser and finding a completely different UI is jarring.

Pick a design and keep it that way, if users aren't satisfied then they can use themes. If you want to give it a new skin then just make a new theme so you don't disrupt users that have already picked one themselves.

[dftf]

To reverse most of the recent change:
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

You can also install the previous theme here:
https://addons.mozilla.org/firefox/addon/firefox-proton/ 

⚠ The ability to reverse Nova may end in Firefox v161, due for release November 24, 2026
Refer to: https://bugzilla.mozilla.org/show_bug.cgi?id=2071454 

[Flame_ONeill]

It looks awful and it's slow.  Fix it.

[dftf]

To mostly-reverse the recent change:
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

You can also install the previous theme here:
https://addons.mozilla.org/firefox/addon/firefox-proton/ 

⚠ The ability to reverse Nova may end in Firefox v161, due for release November 24, 2026
Refer to: https://bugzilla.mozilla.org/show_bug.cgi?id=2071454 

[yaceq]

You destroyed Firefox with this update. I have to restart it 2 -3 times a day because sites don't load. After restart it's ok. Revert all the changes you've done. They're totaly pointless.

Even now, I had to restart Firefox to add this comment!!!

[dftf]

If sites aren't loading, it's probably an extension causing the issue -- a lot of people in the past two days have had loads of issues with YouTube, and the Ghostery extension was the cause.

See if there are any updates for your extensions:
Menu  ->  Extensions and Themes  ->  click the ⚙ icon  ->  Check for updates...

If any get updated, fully-close all Firefox windows, and bring a new one up.

If you still have issues, a custom DNS server you use might be having issues.

Menu  ->  Settings  ->  type DNS into the search box  ->  under "DNS over HTTPS", click "Custom settings"  ->  check the settings there (e.g. click "Custom" and pick a different provider)

[yaceq]

I've been using Firefox for 20 years and have never experienced something like this. I don't use this extension and all mine extensions are up to date. I use cloudflare DNS. 

This loading problem is very strange because when it appears page loads but for example any button doesn't work. it's on every page after 1st appear. Only restart helps but only for some time when it appears again.