i want to change the colour of background how?

hi, if you are on a PC, there is a brush button in the lower right corner, by clicking on which you can change the background of the browser

Hello

A similar discussion https://support.mozilla.org/en-US/questions/1588497

https://superuser.com/questions/1495946/how-do-i-change-the-background-image-of-home-page-in-firefox

For illustration Below, userContent.css, a test performed

For information https://www.firefox.com/en-US/firefox/139.0/releasenotes

A discussion https://support.mozilla.org/en-US/questions/1586459

As for me, i installed Linux, in dual-boot with Windows7