[css-cascade-6] A way for

red

<style scoped> would guarantee that the color only applied to children of the parent div.

I could do it by adding a unique ID or attribute:

red

… this is basically what Vue does at build time. But I want the same effect without a build step!

I think we'd want something like @scope(:style-parent).

red

Otherwise, even with @scope back in play, I'd still have to use a build tool (or something) to generate an ID for the upper bound of the scope.