How do i remove the rounded corners - and floating panels inside firefox?

[monegator]

Today i opened a PDF and i am welcomed with a floating panel and the goddamn rounded corners.

Also, apparently we're getting NOVA.

Thanks, but no thanks

How do i disable those? forever?

Also, fire whoever is pushing the rounded crap without letting the user have their say: material design 3 is crap (looking at you firefox mobile), rounded corners are crap, floating panels are even worse. First think i do on a KDE machine is disable floating panels, and everything goes back to being normal again.

[Fledi]

about:config
browser.nova.enabled
change true to false 

[dftf]

In addition, for the PDF screen, you may need to set "pdfjs.enableNova" to "false" also