"Complete" Dark Theme

Firstly, I know there’s lots of information about dark theme, but I haven’t found a solution to the following.

So, I want a completely dark theme set permanently in Writer. So, even the “page” is black and the text white.

I can do this through "Tools | Options |Application Colours | and change the Document Background, Text Boundaries and Application background (as found on other sites). This works for the document I am working on, but as soon as I upload another document it all goes back to the default black text on white background.

Can anyone help, so I don’t upload a document and get a blast of bright light after having worked on dark theme for a while?

Please name your operating system and the LibreOffice version. Thank you.

Is this on: How to create a default template, so all new files will be white on black?
Or:
Override document settings with dark mode, so black on white documents from other sources will show white on black. What to do with other shadings then? For example keep black on light gray?
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There were a lot of changes during 7.5 and early 7.6 - so your version of LO is essential (and please don’t say “latest”, as this depends on your download source…)

Here you go:

Version: 7.6.4.1 (X86_64) / LibreOffice Community
Build ID: e19e193f88cd6c0525a17fb7a176ed8e6a3e2aa1
CPU threads: 4; OS: Windows 10.0 Build 19045; UI render: Skia/Raster; VCL: win
Locale: en-GB (en_GB); UI: en-GB
Calc: threaded

In the Tools>Options>Application Colors you can save multiple color schemes at the top right. Just hit save, it will prompt you to name your new scheme. I have a dark and a light saved, and it always opens new documents in the scheme I was last using. I’m still on an old version of LibreOffice because I’m lazy, so this should work for anybody 2024 and beyond.