Firefox 157 Brings a Major New Look With Nova and Compact Mode

Image: Mozilla

Mozilla has released Firefox 157, introducing one of the browser’s biggest interface updates in years.

The update brings a redesigned visual system known as Nova, with refreshed tabs, icons, colors, spacing, themes, and browser controls. Mozilla says the redesign is intended to make Firefox feel more modern and flexible while keeping its existing foundation and customization options.

The update is rolling out across desktop and mobile.

A New Look for Firefox

The most noticeable change is the browser interface itself.

Firefox 157 introduces softer tab shapes, updated icons and rebalanced spacing throughout the interface. Mozilla has also refreshed its color palette, including deeper purple tones and a visual glow around the active tab.

The redesign extends beyond the tab bar. Mozilla has updated the appearance of toolbars, the New Tab page, Private Browsing and other parts of the browser to create a more consistent design across Firefox.

Mozilla describes Nova as its biggest Firefox interface refresh since the Proton redesign in 2021.

Compact Mode Returns

One of the most notable changes in Firefox 157 is the return of Compact Mode.

Compact Mode reduces the size of tabs and toolbar elements, allowing more of the screen to be used for webpages. Mozilla also includes an auto-compact option for smaller screens.

The feature returns after users asked Mozilla for a denser browser interface.

For people who prefer seeing more tabs and webpage content rather than larger interface elements, Compact Mode provides an alternative to the default layout.

More Customization

Firefox 157 also gives users more control over how the browser looks.

Mozilla has introduced a new theme picker that makes it easier to change Firefox's appearance. New themes and wallpapers are available, while the existing community theme ecosystem remains available through Firefox's add-ons system.

The New Tab page is also becoming more customizable. Users can organize and pin shortcuts to keep frequently visited websites accessible from the homepage. Mozilla says this functionality is rolling out gradually.

Sidebar and Vertical Tabs Get More Attention

Nova also changes how Firefox handles the sidebar.

The sidebar now shares more of the browser's visual background with the toolbar, creating a more unified interface. Vertical tabs are also treated as a first-class layout rather than simply an alternative arrangement.

This is particularly relevant for users who keep large numbers of tabs open and prefer managing them vertically.

Mozilla has also made several changes to how themes interact with the sidebar and vertical-tab layout.

What Hasn't Changed

Despite the visual overhaul, Firefox 157 is not a completely new browser.

The update keeps Firefox's existing foundation, including its open-source development model, privacy protections and customization controls.

Mozilla also says the redesign itself does not come at the expense of browser performance. The company has separately reported improvements to loading and scrolling, while the new interface is primarily focused on usability, appearance and customization.

What About Existing Themes?

Existing Firefox themes should continue to work with Nova, although some can look different because the browser's interface surfaces have changed.

Mozilla specifically notes that themes using background images may require attention because images can now appear in areas such as the sidebar and vertical-tab interface.

Theme developers may need to adjust certain properties to make their designs fit the new interface correctly.

Firefox 157 at a Glance

Version: Firefox 157
Major design: Nova
Platforms: Desktop and mobile
Interface: Refreshed tabs, icons, colors and spacing
Compact Mode: Returns
Themes: New themes and easier theme selection
New Tab: More customization and pinnable shortcuts
Sidebar: More integrated with the browser interface
Vertical tabs: More deeply integrated into the layout

The Bigger Change

Firefox 157 is more than a collection of redesigned icons and tabs. Mozilla is using Nova as a new visual foundation for Firefox, bringing the browser's desktop and mobile interfaces closer together while giving users more control over appearance and layout.

The return of Compact Mode is particularly notable because it shows that Mozilla is not simply moving toward a larger, more spacious interface. Users can now choose between a more relaxed default layout and a denser configuration designed to make better use of screen space.

Firefox 157 is therefore a significant visual reset for Mozilla's browser, but the underlying Firefox experience remains familiar.