Two brand new themes will ship as part of the next release of Mozilla Firefox.

Firefox 53, which is due for release in April and is currently in beta, features new ‘compact’ light and dark themes.

Both themes are preinstalled and shipped alongside the regular defaultFirefox theme. They are entirely optional and are not enabled by default.

Wondering what they look like?

The New Firefox Compact Themes

Compact Light:

Compact Dark:

And, in case you’ve forgotten what the default Firefox theme looks like, here’s a refresher:

The ‘Dark Compact’ theme will be recognisable to those who’ve used Firefox Developer Edition, where it is used by default.

The compact themes (as you might have guessed) are designed to save a couple of vertical pixels versus the standard, more spacious theme.

And on certain desktops, like macOS, the difference is evident:

But on Ubuntu Linux, where Firefox uses a traditional window title bar, the vertical savings, if any, are harder to spot:

Neither of the these new themes are connected to Mozilla’s more dramatic Firefox redesign plans, which are known as ‘project photon‘.

Enable Firefox Compact Themes

To take the themes for a test drive you’ll need to download the latest beta release of Firefox. There are various ways to get it, but I’d recommend downloading and running the binary so as not to affect your stable, Canonical-supported build.

Download the latest Firefox Beta

Then, once running, head to the Add-on Manager via Menu > Add-ons > Appearance or Tools > Add-ons > Appearance .

Click on the ‘enable’ button the Compact Dark or Compact Light themes listed with the default theme (and any other themes you may have installed) to activate your chosen theme.

Changes are applied instantly so you won’t need to restart the browser.

Let us know what you make of these (admittedly modest) new themes in the cavernous comments hole below.