Firefox gemenskapsforum

So I wanted to read PDFs trough firefox with a dark theme, looked up how to do so online, and people say to change the "about:config" option "pdfjs.viewerCssTheme" to "2" instead of "0", I did that, tried opening a PDF, nothing happend, it was still black text on white backgrounds. Tried closing firefox, reopened the pdf, nothing happened, still white backgrounds. Tried to check if it might have to do with that specific pdf file's config, created my own PDF file from a word document, tried to open it, still white backgrounds. Tried disabling extensions, (which I use four of, UBlock Origin, SponsporBlock, Return Youtube Dislike and Translate this page), didn't work. Tried enabling the option on my laptop, didn't work. Tried a bunch of other stuff and it still won't work. My Firefox version is 109 and I'm using Windows 10 I also don't want to use the console/file edit thing with grayscale(1) invertcolor(1) or whatever it was since it also reverses the colors of images instead of just the backgrounda nd text color.

I have Firefox set to "view PDF files in Firefox", but this is not happening with sites like Capital One and Consumer's Energy. these sites are just saving directly to my downloads folder even though I 1) Want to view the file first and 2) if it is going to save a flle, it is set up to ask where the file should be saved.

Neither of these things are happening even though I have them set up correctly in Settings.

Firefox has started making a piercing high-pitched screech when the "save image" and "file update" panels appear. This is a confirmation or alert sound I suppose. It occurs when saving an image from a right-click menu and when downloading a file. Formerly Firefox used the system default sound for this, and that sound is still working in other programs for similar operations.

How can I fix this? Or alternatively how can I disable the sound during such operations in Firefox (or alternatively system-wide)?

Good day, has anybody an idea if and what addon could manage for me redefinition of mouse behaviour. Particularly in my case I want to use middle (wheel) button single click over any text input to perform clipboard paste (but everywhere else the button behaves normally). I had this feature integrated into mouse gestures add on which is no more compatible.