ladybird/Libraries/LibWeb/CSS/CSSScopeRule.idl

// https://drafts.csswg.org/css-cascade-6/#the-cssscoperule-interface
[Exposed=Window]
interface CSSScopeRule : CSSGroupingRule {
    readonly attribute CSSOMString? start;
    readonly attribute CSSOMString? end;
};
LibWeb/CSS: Implement the `@scope` rule `@scope (a) to (b) {}` applies its contained style rules to elements that have `a` as a parent, and do not have `a b` as a parent. Both the `a` and `b` selector lists are optional. Because it's situational whether a `@scope` will apply to a given element, we store the ancestor scope on the `MatchingRule`, similar to `@container`, and then determine during matching whether all the parent `@scope`s match or not. The rules for how selectors inside `@scope` are adjusted and interpreted are a bit confusing. Unlike for other at-rules, nested style rules inside `@scope` do not get a leading `&` added during parsing. To support this, `adapt_nested_relative_selector_list()` now takes a flag for whether its parent is a `@scope` or not. `@scope` can also contain nested declarations without itself being nested inside a style rule. When determining their selectors, nested declarations rules adopt the `@scope`'s scoping root if it has one, or otherwise fall back to the parent element of the `<style>` element (not implemented here,) or the `:root`. These are required to have zero specificity, so we wrap the selector in `:where()`. 2026-05-15 17:11:08 +01:00			`// https://drafts.csswg.org/css-cascade-6/#the-cssscoperule-interface`
			`[Exposed=Window]`
			`interface CSSScopeRule : CSSGroupingRule {`
			`readonly attribute CSSOMString? start;`
			`readonly attribute CSSOMString? end;`
			`};`