If you like to manually write custom CSS rules for every website that you visit, you could use Stylus. That would be fast.
Additionally, websites that use Bootstrap >=5.3 actually do have adaptive dark/light mode that gets set automatically as long as your browser communicates that to the website in question. So this isn’t universal, or even well adapted, but this is also fast.
If you like to manually write custom CSS rules for every website that you visit, you could use
Stylus
. That would be fast.Additionally, websites that use
Bootstrap >=5.3
actually do have adaptive dark/light mode that gets set automatically as long as your browser communicates that to the website in question. So this isn’t universal, or even well adapted, but this is also fast.