How to have a dark / black Quick Settings (swipe down) menu on Oreo 8.1?

I always used to have a dark or black Quick Settings (the swipe down menu) but since Android , it's white. And I can't find out how to change it. Invert Colors is not an option, as that messes up *all* colors on my phone whereas I only want to change the Quick Settings. When searching on this problem I did find several apps (some of which even require root) to change the theme, but I can't imagine something so trivial really requires a custom app or even root. Using Oreo 8.1 stock Android with all latest updates, no root. ------- Upon further searching, I found a partial solution: apparently if you set a "dark" wallpaper for your Home screen, it will automatically show the Quick Settings menu in dark instead of white. Beats me why this can't just be customised manually, but for your reference: for example with the wallpaper below, I get a dark Quick Settings menu on Oreo 8.1 instead of white.
" class="img-fluid rounded" style="max-width: 100%; height: auto; margin: 10px 0;" loading="lazy"> No clue what the criteria may be for a wallpaper to be "dark enough". If there is a definitive solution I'd still love to find out!