Add CSS property

[ByteEater-pl]

Per the separation of concerns principle, the markup should only specify semantics. Polluting it with template children when the purpose is purely stylistic goes very much against it, is inelegant, verbose, and hurts readability. And, as the blog post mentions, suffers from lack of reusability. It would be better to be able to define templates out of band (e.g. inside head or in a different resource altogether) and reference them using CSS. I.e. bring back the binding property from XBL. And events for attaching and detaching, for situations in which the author wishes to go beyond declarativity and resort to scripting.

[mfreed7]

Thanks for the comment. Remember that the purpose of declarative shadow dom is to allow shadow trees of all kinds to be represented in HTML, not just the ones used for “purely stylistic” reasons. For example when serializing custom elements that use shadow dom. I’m not sure re-structuring the DOM tree via CSS is a great idea - are there any other such precedents?