How can I enable dark mode on Firefox on Windows 7 so that the settings page has a dark mode?

How can I enable dark mode on Firefox on Windows 7 so that the settings page (about:preferences#home) has a dark mode?

I unsuccessfully tried:

• using the Dark Reader Firefox extension.
• using Firefox' native dark mode (customize -> themes -> dark)

The settings page:

Solution 1:

Great answer by Backseat-Driver on reddit:

You can tell Firefox that you want dark mode by adding ui.systemUsesDarkTheme [number] in about:config and setting the value to 1.

• 0: light
• 1: dark
• 2: no-preference

Any other value and Firefox will use light.

Tested with Firefox 75.0 64-bit on Windows 7 SP1 x64 Ultimate.