[csswg-drafts] [css-shadow-parts] Limited ::theme selector (#3507)

frivoal has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-shadow-parts] Limited ::theme selector ==
(Split from issue #3467, reported by @stefsullrew)

The current description of the *::theme* selector is perhaps a bit too broad for real world usage. However the ability to access any *::part* within the context of a component, without elaborate `exportparts=` chains would be much easier to work with in the context of a design system.

In the example below, a theme context is defined for `**x-foo**` with the prefix of “`foo-`*”*. This would grant access to all child parts that match the name within the declared theme's context. This scoping limits the reach of *::theme* while avoiding the potentially complex *exportparts=* chains. Particularly when there's deep composition of components not owned by a single team.

```
<x-foo theme="foo-">
    <x-bar></x-bar>
    <x-oof></x-oof>
</x-foo>


// x-bar definition
<x-bar>
    <p part="metadata">Posted on: 2019-01-10</p>
</x-bar>

// x-oof definition
<x-oof>
    <svg part="icon"></svg>
</x-oof>
```

```
x-foo::theme(foo-metadata) {
    color: grey;
    font-style: italic;
}
```


Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3507 using your GitHub account

Received on Monday, 14 January 2019 02:59:26 UTC