As a user, I'm really excited about this. There are still so many websites that don't support dark mode.
Having built websites myself, I know how much attention it takes to make sure every page and component looks good in both light and dark mode.
It's not perfect yet. Even in the second demo, you can see that the chart remains white, creating a stark contrast with the rest of the page. But it's a great step toward making dark mode work across the web without requiring every developer to implement it themselves.