Firefox version 157 is very round (and how to make it less round)

Very, very round.

Firefox version 157 (Nova) “refreshes” the interface by taking the very, very round corners found in macOS Tahoe and applying them across everything in the browser.

I thought I remembered reading it would come with a control to let you set the roundness of the corners of various elements, because, as mentioned, they are very, very round. But I appear to have misremembered.

There is a way to turn the roundness off, described below. The option may disappear in the future, but it’s there, for now.

Revert Firefox to pre-Nova/157 look

1. Enter about:config in the address bar and click the button to proceed if you get a warning.
2. Search for nova.
3. Click on the option browser.nova.enabled and set it to false.
4. Restart Firefox (may not be necessary).
5. Enjoy the pre-157 look.

The full manual control version

This keeps Nova, but lets you set how round various UI elements will be. I found it created some visual weirdness, but that might just be on my system.

1. Enter about:support in the address bar.
2. Under Application Basics find Profile Folder and click the Open Folder button.
3. Create a folder in your profile folder called Chrome.
4. Create a file in the Chrome folder called userChrome.css.
5. Add this to the user.css file, save it and restart Firefox:

/* Force square corners on all Firefox UI elements */

{

  border-radius: 0px !important;

}

Set the px value to 0 for a fully sharp-edged experience. If you want a little roundness, adjust the value to taste. Somewhere around 4px-6px is close to pre-Nova.