[css-anchor-position] Switch the OM to the @page model. w3c#10108

Author: tabatkins

css-anchor-position-1/Overview.bs

@@ -2054,24 +2054,108 @@ The CSSPositionTryRule interface {#om-position-try}
 The {{CSSPositionTryRule}} interface represents
 the ''@position-try'' rule:
 
-<pre class='idl' export>
+<xmp class='idl' export>
 [Exposed=Window]
 interface CSSPositionTryRule : CSSRule {
 	readonly attribute CSSOMString name;
-	[SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+	[SameObject, PutForwards=cssText] readonly attribute CSSPositionTryDescriptors style;
 };
-</pre>
+
+[Exposed=Window]
+interface CSSPositionTryDescriptors : CSSStyleDeclaration {
+	attribute CSSOMString margin;
+	attribute CSSOMString marginTop;
+	attribute CSSOMString marginRight;
+	attribute CSSOMString marginBottom;
+	attribute CSSOMString marginLeft;
+	attribute CSSOMString marginBlock;
+	attribute CSSOMString marginBlockStart;
+	attribute CSSOMString marginBlockEnd;
+	attribute CSSOMString marginInline;
+	attribute CSSOMString marginInlineStart;
+	attribute CSSOMString marginInlineEnd;
+	attribute CSSOMString margin-top;
+	attribute CSSOMString margin-right;
+	attribute CSSOMString margin-bottom;
+	attribute CSSOMString margin-left;
+	attribute CSSOMString margin-block;
+	attribute CSSOMString margin-block-start;
+	attribute CSSOMString margin-block-end;
+	attribute CSSOMString margin-inline;
+	attribute CSSOMString margin-inline-start;
+	attribute CSSOMString margin-inline-end;
+	attribute CSSOMString inset;
+	attribute CSSOMString insetBlock;
+	attribute CSSOMString insetBlockStart;
+	attribute CSSOMString insetBlockEnd;
+	attribute CSSOMString insetInline;
+	attribute CSSOMString insetInlineStart;
+	attribute CSSOMString insetInlineEnd;
+	attribute CSSOMString top;
+	attribute CSSOMString left;
+	attribute CSSOMString right;
+	attribute CSSOMString bottom;
+	attribute CSSOMString inset-block;
+	attribute CSSOMString inset-block-start;
+	attribute CSSOMString inset-block-end;
+	attribute CSSOMString inset-inline;
+	attribute CSSOMString inset-inline-start;
+	attribute CSSOMString inset-inline-end;
+	attribute CSSOMString width;
+	attribute CSSOMString minWidth;
+	attribute CSSOMString maxWidth;
+	attribute CSSOMString height;
+	attribute CSSOMString minHeight;
+	attribute CSSOMString maxHeight;
+	attribute CSSOMString blockSize;
+	attribute CSSOMString minBlockSize;
+	attribute CSSOMString maxBlockSize;
+	attribute CSSOMString inlineSize;
+	attribute CSSOMString minInlineSize;
+	attribute CSSOMString maxInlineSize;
+	attribute CSSOMString min-width;
+	attribute CSSOMString max-width;
+	attribute CSSOMString min-height;
+	attribute CSSOMString max-height;
+	attribute CSSOMString block-size;
+	attribute CSSOMString min-block-size;
+	attribute CSSOMString max-block-size;
+	attribute CSSOMString inline-size;
+	attribute CSSOMString min-inline-size;
+	attribute CSSOMString max-inline-size;
+	attribute CSSOMString placeSelf;
+	attribute CSSOMString alignSelf;
+	attribute CSSOMString justifySelf;
+	attribute CSSOMString place-self;
+	attribute CSSOMString align-self;
+	attribute CSSOMString justify-self;
+	attribute CSSOMString positionAnchor;
+	attribute CSSOMString position-anchor;
+	attribute CSSOMString insetArea;
+	attribute CSSOMString inset-area;
+};
+</xmp>
 
 Its <dfn attribute for=CSSPositionTryRule>name</dfn> attribute
 represents the name declared in the rule's prelude.
 
 Its <dfn attribute for=CSSPositionTryRule>style</dfn> attribute
-represents the styles declared in the rule's body,
+represents the properties declared in the rule's body,
 in the specified order.
-Only the [=accepted @position-try properties=] are valid in this rule.
-
-Issue: match the concept of validity to whatever we do in similar situations.
-
+On getting, it must return a {{CSSPositionTryDescriptors}} object
+for the ''@position-try'' at-rule,
+with the following properties:
+
+: [=CSSStyleDeclaration/computed flag=]
+:: Unset
+: [=CSSStyleDeclaration/readonly flag=]
+:: Unset
+: [=CSSStyleDeclaration/declarations=]
+:: The declared descriptors in the rule, in <l spec=cssom>[=specified order=]</l>.
+: [=CSSStyleDeclaration/parent CSS rule=]
+:: The context object
+: [=CSSStyleDeclaration/owner node=]
+:: Null
 
 <h2 id=interleaving>
 Appendix: Style & Layout Interleaving</h2>