Comment by nextaccountic

there's a firefox (maybe chrome too) extension called dark reader

not only it wil dark-ify pages that don't support dark mode, it will alter the tone of dark mode pages to a more enjoyable (i like to add some pastel colors)

for dark mode pages that are already perfect, you can disable it on a per page basis

only trouble i had so far is that disabling or enabling happens per-site. so I can't have dark mode on google, disabling it on google maps