So out of nowhere firefox changed my blank tab background to dark and google website background to dark. I tried messing around with the themes and now stupid color theme keeps automatically switching to default. It used to be so easy to remove the themes and to change the default theme. Not there is no button for it. So f.... frustrating to look at this. I want to uninstall the themes and i can't the 3 dots have only manage button and nothing there to remove the theme or to set as default.

So how do i set my default theme and get rid of the rest of the theme garbage? Thank you