At first glance, this looks like a terrible idea. But the key is in the implementation. In this case, the implementation is truly awful.
The section on detecting “auto dark theme” is, as far as I can tell, not intended as a joke.
Mind you, this could all be a galaxy-brain idea to encourage more developers to provide their own dark mode styles. (In much the same way that AMP was supposed to encourage better performance.)
There’s a nice shout-out from Jen for Resilient Web Design right at the 19:20 mark.
It would be nice if the add-to-homescreen option weren’t buried so deep though.
I really like the idea of a shared convention for styling web components with custom properties—feels like BEM meets microformats.
Here’s a clever shortcut to creating a dark mode by using mix-blend-mode: difference.
I had to read through this twice, but I think I get it now (I’m not the sharpest knife in the drawer). Very useful if you’re doing theming in CSS.
On Ev’s blog, Marcin goes into great detail on theming an interface using CSS custom properties, SVG, HSL, and a smattering of CSS filters.
I was kind of amazed that all of this could happen via CSS and CSS alone: the colours, the transitions, the vectors, and even the images.
Harry demonstrates a really good use for CSS custom properties—allowing users to theme an interface.