On Android, Vivaldi supports dark more out of the box. It's actually just a toggle for the dark mode present on any chromium-based browser, and you can enable it globally in any of them in chrome://flags/#enable-force-dark
Dark Reader, often recommended, is very slow, especially on old hardware. This built-in mode is much more efficient and works well on vast majority of pages.
Dark Reader, often recommended, is very slow, especially on old hardware. This built-in mode is much more efficient and works well on vast majority of pages.