Re: [webcomponents] Should shadow host have `display: block` by default? (#426)

`:host` is a very special pseudo class, defined in https://drafts.csswg.org/css-scoping/#host-selector.

e.g.
It is declared in a shadow tree, A, but it does not match any element in A. Instead, it matches the shadow host which hosts A.

> Would :custom apply to only custom elements, or would it also apply to undefined potentially-custom elements (i.e. any element whose name is a valid custom element name)?

I thought that `:custom` only checks the element name. It is `:custom-element-name`, in other words.

---
Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/issues/426#issuecomment-194669443