Take Project Nova for a spin in Nightly!

[AshleyT]

Hi there! I'm Ashley, Senior Staff Product Manager for Firefox. After months of updates on Project Nova, it's finally in Nightly, ready for you to see for yourself. We're modernizing Firefox from the ground up to ensure it remains a fast, secure, and highly customizable companion for today’s internet.

This is still early days, so you'll notice some rough edges — a few things may look unfinished or inconsistent for now. Keep your Nightly up to date to see the latest. 

As a reminder, the Project Nova updates include:

• Simpler navigation and a redesigned Settings experience, now live in release
• Refreshed tabs, icons, spacing, and browser surfaces
• More ways to make it yours, with rich new themes, wallpapers, and personalization options that let Firefox match your style.

We're grateful for all the thoughtful feedback we got on our earlier Connect post, on social media, and through user research. Based on what we heard, we've made some changes:

• We'll be experimenting with corner roundness settings for tabs to give you more options — coming soon in Firefox Labs.
• We brought back Compact Mode so there’s more space for web content and tabs
• We added more neutral standard theme options.

You can learn more in our blog post.

See it first in Nightly

Nightly is where this work takes shape in the open, and we wanted you to be among the first to see where it's headed. Since much of what’s changed so far focuses on the look of the interface, keep an eye out for how these layouts feel during your day-to-day browsing. We're aiming for a clean, intuitive experience —so please look out for anything that feels off, like icons, spacing, alignment, or how things hold up across themes, window sizes, different languages, screen readers, and keyboard navigation. If something catches your eye, we'd love to hear about it.

Download the latest version of Nightly to see what's new.

Something's not right? File a bug.

If you find visual or functional issues with the Nova style changes in Nightly, please follow these steps:

1. Click this link to file a Bugzilla issue. We're asking everyone to file bugs this way, so we can easily keep track of all issues reported.
2. In the bug, please add steps to reproduce the issue, and if possible screenshots or screencasts. Please don't add severity and priority to the bugs — our triaging teams will handle that.
3. You can see all Nova testing bugs filed here.

Have overall feedback? Let us know here in Connect.

Drop a comment here to let us know your thoughts and suggestions. Thanks for being part of this.

[404usrnamefound]

Is there any plans to add automatic history and cache/session token syncing across devices? I know there's tab syncing but it would be nice to have history and cache/session token, so people don't have to manually sign in on each new device.

[Xufox]

After trying this for a few days, I found the borders around the window to be extremely problematic since it violates the “rule of the infinite edges” (see Fitts’s Law), i.e. UI elements at the edge of the screen are suddenly much harder to reach and click on.

[sosasees]

I tried the Nova Redesign.

I believe it will end up better than current Firefox because it visually differentiates UI Elements much more clearly. But the new Borders are an Overcorrection.

This Sketch shows approximately the actual Nova Borders on the left and how i would change the Borders on the right.

It’s a good Thing that the Borders have become thick and distinct so that i can better tell where each major Section of the Browser UI begins and ends (Top Bar, Sidebar, and Web View).

But the current Design of each Section being inside a Panel looks ridiculous, as if the Firefox Window is a Hardware Device with 3 distinct Screens.

I would get rid of the alternating grey‑white‑grey Borders, instead making them one Color throughout. Then reduce their border-width to 2pt, which looks much more lightweight.

The interactive Borders usable to resize Windows can be thicker than the visible Borders that they overlap. Take Advantage of that Trick.

Edit: I found the Compact Density Setting, which does pretty much exactly that. Only it still needs to make the usable Border for resizing the vertical Tab Bar thicker than the visible Border.

Edit 2: I still believe that making the Borders only one Color would look much more elegant in all Densities.

[sosasees]

The very rounded Borders look very good but i believe Nova has too much of this good Thing right now.

This Shape is effetive in Key Places like the Address Bar, Call‑to‑Action Buttons, and Dialog Buttons.

It’s not so good for denser UI like Tabs and Menus. The Circles everywhere make secondary and tertiary UI Elements feel cramped, even if i set the Density to Touch.

[MozUsr]

Congratulations, you have won the ugliest UI design of the year award! 

[crystall]

I'm not fond of the new look, the coloring and design is very flat and generic. Most applications and webpages designed in the past 10+ years share this flat and minimalistic style so Firefox doesn't stand out much. There is also some wasted space in the UI and the tabs appear even more disconnected from their contents than in the past. I would like to be able to put them below the URL bar again. On the upside I'm very glad that compact mode is officially supported again as it helps free up precious screen space. The new settings is also a big improvement over the old ones.

[bitofabother]

Apologies if this double posted thanks to login troubles.

This is... bad. The padding and rounding look amateurish at best -- it blocks content, collides with the menu items, and generally looks like I've got a UI zoom set to about 50% larger than I can stand to use. On Windows 11 it might vaguely match the (bad) rounding that's in place everywhere. On an OS without it, it's jarring and looks like something is wrong -- I honestly thought my nightly instance was broken for a bit after the update rolled out.

Legitimately, if you force this without changes, I think it'll be my last straw on not switching to another browser.

[sajidanwar]

Overall, I think I like the look, but I'm not a fan of the default gradients that it comes with -- in dark mode, the muddy purple to orange is offputting and I don't love the other color choices.

I do really quite like the Firefox Alpenglow theme on dark mode with Nova though! I think it's because of how the rounded elements of the chrome, like the toolbar up top, sidebar, and the web content itself feels layered "on top of" so-to-speak the Alpenglow background. In the default color themes, they instead feel like really disconnected cards floating on a blank canvas. Official themes like Dreamer - Bold (which I might switch to) or even Expressionist - Balanced look better for this reason, the colors on the elements are much more integrated.

Maybe the onboarding experience of the theme picker would make it easier for me to select the thing I like (or understand what I don't like). Is there some way to see that onboarding experience again without a full new install so I can try to give feedback on that?

[VS2]

Really dont love the chrome style pill shape for tabs. More than anything else though, having unclickable padding space above the tabs and corner window buttons is infuriating. 

[Bennytek]

My opinion seems to differ a fair bit from the others that I've seen after a brief look through the comments here, but I absolutely love the new design introduced in Nightly! I think everything looks absolutely fantastic (especially the tabs!), and I haven't had any functionality issues that I've run into yet.

I used to exclusively use Vivaldi on desktop, but I'm loving my time with Firefox Nightly currently!

[Jazgot]

I don't like a new look, mostly because of too much is going on. Tabs should be simple and do not obstruct or interfere with the content. New ones are colourful and shiny, immediately grabbing attention. Colour gradients are frustrating for me too. No matter how hard you try, this always keep me thinking about end and beginning of a gradient. I'd call new redesign as busy, calling attention instead of being sleek like previous one.

[devXD]

ash theme

[colortraks]

who thought it would be a good idea to surround the viewport with an unnecessary 5 pixels of spacing on each side? even in a maximized window ....? im disappointed 😞

[SpockData1]

I actually like the modular design of the UI. I LOVE the new pill shaped rainbow-colored Tabs

[Merci-chao]

The container tab line looks awkward in 155.0a1 (2026-08-04), especially on pinned tabs and in split views. In 154, the line looks much more elegant.

[vpi]

When I click the top pixel of the screen in a maximised firefox, it does not select the tab. I hope that's a bug in my version and not the intended behviour. Otherwise, round or square, I don't really care

[faubulous]

I like the new look! Great work and respect for taking the courage to try something new. The only thing I'd like to see improved are the tab groups. I'm using workspaces a lot with Zen and can't live without it. Tab groups come closest but can't really compete at the moment when it comes to focus and reduced clutter. Anyway. Keep up the good work! 👏

[devXD]

Its Cool

[sosasees]

I noticed many People have opposing Views on how much the Interface should be rounded.

There should definitely be Options to change the Default. From easy Presets to set everything a certain Level of Roundness, to customizing Controls of every Type (Tabs, Address Bar, Menu Buttons, Dialog Buttons).

Maybe we could even choose from all 6 corner-shape's, because the whole Firefox Interface already uses CSS for Styling.

[deniable4z]

I don't think this is the right solution. As the new design demonstrates, changing the corner radius often also requires adjusting the padding and font size. Adding even more options will only make the code harder to maintain.

[sosasees]

That’s a very good Point.

I hope Nova won’t ship for a good While, so that Mozilla has enough Time to resolve the rounded Edges Controversy.

If i was a Designer in this Situation, i would wish to just revert to moderately rounded Corners.

Mozilla did state that Nova should feel familiar, and the current Design does not feel very familiar — except to Apple Users who have to put up with the same extreme Rounding in the “Liquid Glass” Design Language.

Pretty much the only UI Elements that have this much Rounding by Default in most other Browsers are the Address Bar and maybe Dialog Buttons.

[allezlol156]

Hi, ok for pills tabs but if the mouse is at the top of the screen it doesn't select the tab thats annoying 🙂

[mtantawy]

Love the new look actually!

Also the new way a tab is colored based on its container is really cool

I haven't explored the rest of the changes yet but once I restarted firefox nightly and got the new look I liked it

[deniable4z]

IF YOU SHIP THE NEW DESIGN, I WILL NEVER USE FIREFOX AGAIN.

I love Firefox. No other browser offers such a powerful set of features, including bookmark management, tab containers, tab groups, and so much more. I use Firefox for hours every single day.

But with the new design, it feels like the browser is en**bleep**tifying right before my eyes. Please don't sacrifice a great user experience in pursuit of a trend. Revert the Nova design.

[JoshT]

I'm trying to use the new vertical tabs feature, but after using it for a couple of hours now, there's three things about it that feel unnatural to me:

1. The new tab button is at the bottom of the tab list, far away from the URL bar at the top of the window. It's a big distance between two interconnected things. I'd like an option to reverse the order of the tabs and have the newest tabs appear at the top.
2. I like the option to expand the vertical tabs sidebar on hover. But to close a tab, I can't do it quickly. I have to hover, wait for the sidebar to expand, and then move my cursor to the right side of the tab. But if I move my cursor too far, the sidebar collapses again. I'd like the close button to still be over the favicon, like with the always collapsed version of the vertical tabs.
3. With horizontal tabs in a maximised window on Windows, I can't move my cursor to the top of the screen and click a tab any more. With Fitts Law, I could click on a tab very quickly when the hit area of a tab touched the top of the screen when the window was maximised.

[Sangligli]

I don't like that the search bar is surrounded by a line. There are already a lot of lines from the different sections, and it makes the interface look cluttered and not visually pleasing. Nothing to say about the colors and roundness of the interface tho.

For exemple there is a line arround the search bar + arround the toolbar + arround the content:

Also, bookmarks toolbar shouldn't cause vertical tabs elements to move vertically on New Tab page. It's messing with muscle memory and is the one and only reason why I still don't use the vertical tabs:

[sosasees]

It would be much more elegant if setting the Bookmarks Toolbar to "Only on new Tabs" would change the Bookmarks Toolbar to be built into the "new Tab" Page itself.

[Chaz6]

I appreciate the effort that has been put in, but sadly it is not for me. I strongly dislike the rounded elements and wasted space. I am grateful that I can disable it by setting browser.nova.enabled = false

[MozUsr]

You should scrap this design entirely. I saw 1 bug fix few days ago. I wanted to let you know that there is no point fixing it, this design must be reverted to old one entirely. Stop wasting your time on design that is not needed or wanted and do something useful instead. Some bugfixes here or there wont make us embrace your ugly rounded corners. You need to revert this design entirely. It's a bad decision, you got enough feedback from people that it's bad decision. Stop it. Even AI would have designed better UI.

[sosasees]

I have commented this before in Text-only
but now i can show it with an Edit in GIMP.

The new two-colored Borders around the major Areas of the Browser (Top Bar, Sidebar, and Web View) look too detailed and have low Contrast:

Changing the whole Border to just one Color makes it much more visible and elegant:

[sosasees]

I love the Tab Bar Gradients that are bundled in Firefox Nightly with Nova.

So i believe the Firefox Color Add‑on should get a Way to easily make my own such Gradients, without uploading an Image, with just choosing 2 Colors — or 3 Colors, for a better Transition.