Support MacOS Mojave Dark Mode

[gjsman]

https://kevinchen.co/blog/support-macos-mojave-dark-mode-on-websites/

If you could support this, that would be great!

[David-Griffiths]

Agreed, this would be nice to have.

I'll add to the list.

[gjsman]

https://webkit.org/blog/8718/new-webkit-features-in-safari-12-1/

[gjsman]

I actually just semi-implemented this myself in my Nova site.

I copied-pasted the styles from the extension and wrapped them in the @media section from the blog post. It worked pretty well. The only thing that didn't work was that the slider said Dark Mode was off, and switching it on/off didn't do anything. Close, but not quite there.