[css-pseudo-4] Move part-like pseudo-elements chapter

Author: fantasai

css-pseudo-4/Overview.bs

@@ -1362,7 +1362,7 @@ Security Considerations for Highlighting</h3>
   the styling of such highlighted segments.
 
 <h2 id="treelike">
-Tree-Abiding and Part-Like Pseudo-elements</h2>
+Tree-Abiding Pseudo-elements</h2>
 
   <dfn export lt="tree-abiding|tree-abiding pseudo-element">Tree-abiding pseudo-elements</dfn> always fit within the box tree.
   They <a lt="inheritance">inherit</a> any inheritable properties from their <a>originating element</a>;
@@ -1373,52 +1373,6 @@ Tree-Abiding and Part-Like Pseudo-elements</h2>
     parsing/tree-abiding-pseudo-elements.html
   </wpt>
 
-<h3 id=partlike>
-Part-Like Pseudo-Elements</h3>
-
-  A subset of [=tree-abiding pseudo-elements=],
-  the <dfn export lt="part-like|part-like pseudo-element">part-like pseudo-elements</dfn>,
-  have slightly stronger requirements:
-  they act as if they have a well-defined location in the document tree.
-  This enables them to interact with some other platform features
-  as if they were real elements
-  (and, in fact, they often <em>are</em> real elements,
-  such as in the case of ''::part()'',
-  which simply aren't accessible in the current tree).
-
-  [=Part-like pseudo-elements=] inherit from their [=originating element=] by default,
-  like a standard [=tree-abiding pseudo-element=],
-  but can declare that they inherit from another element instead
-  (possibly not accessible).
-  (For example, ''::part()'' inherits from
-  the parent of the element it represents in the shadow tree.)
-
-  All pseudo-classes and pseudo-elements
-  are syntactically allowed after a [=part-like pseudo-element=],
-  such as ''x-button::part(label):hover''
-  or ''x-button::part(label)::before'',
-  but some are disallowed from matching:
-
-  * The [=structural pseudo-classes=],
-    '':has()'' pseudo-class,
-    '':scope'' pseudo-class,
-    and '':host''/'':host()''/'':host-context()'' pseudo-classes
-    never match.
-  * ''::part()'' never matches. (Other [=part-like pseudo-elements=] can, however.)
-
-  A [=part-like pseudo-element=] can define itself as representing a real element
-  (possibly not accessible in the current tree).
-  If it does so, all pseudo-classes and pseudo-elements match according to that element,
-  if not disallowed by the previous restrictions.
-  If it does not do so,
-  it must define which pseudo-classes it matches and when
-  (besides the pseudo-classes defined to work on all pseudo-elements,
-  or all [=tree-abiding pseudo-elements=]).
-
-  Unless otherwise specified,
-  any CSS property that applies to elements
-  applies to [=part-like pseudo-elements=].
-
 <h3 id="generated-content">
 Generated Content Pseudo-elements: ''::before'' and ''::after''</h3>
 
@@ -1624,6 +1578,53 @@ Placeholder Input: the ''::placeholder'' pseudo-element</h3>
   It's not clear how this should work, but it may be worth doing.
   See <a href="https://github.com/w3c/csswg-drafts/issues/2517">Issue 2417</a>.
 
+<h2 id=partlike>
+Part-Like Pseudo-Elements</h2>
+
+  A subset of [=tree-abiding pseudo-elements=],
+  the <dfn export lt="part-like|part-like pseudo-element">part-like pseudo-elements</dfn>,
+  have slightly stronger requirements:
+  they act as if they have a well-defined location in the document tree.
+  This enables them to interact with some other platform features
+  as if they were real elements
+  (and, in fact, they often <em>are</em> real elements,
+  such as in the case of ''::part()'',
+  which simply aren't accessible in the current tree).
+
+  [=Part-like pseudo-elements=] inherit from their [=originating element=] by default,
+  like a standard [=tree-abiding pseudo-element=],
+  but can declare that they inherit from another element instead
+  (possibly not accessible).
+  (For example, ''::part()'' inherits from
+  the parent of the element it represents in the shadow tree.)
+
+  All pseudo-classes and pseudo-elements
+  are syntactically allowed after a [=part-like pseudo-element=],
+  such as ''x-button::part(label):hover''
+  or ''x-button::part(label)::before'',
+  but some are disallowed from matching:
+
+  * The [=structural pseudo-classes=],
+    '':has()'' pseudo-class,
+    '':scope'' pseudo-class,
+    and '':host''/'':host()''/'':host-context()'' pseudo-classes
+    never match.
+  * ''::part()'' never matches. (Other [=part-like pseudo-elements=] can, however.)
+
+  A [=part-like pseudo-element=] can define itself as representing a real element
+  (possibly not accessible in the current tree).
+  If it does so, all pseudo-classes and pseudo-elements match according to that element,
+  if not disallowed by the previous restrictions.
+  If it does not do so,
+  it must define which pseudo-classes it matches and when
+  (besides the pseudo-classes defined to work on all pseudo-elements,
+  or all [=tree-abiding pseudo-elements=]).
+
+  Unless otherwise specified,
+  any CSS property that applies to elements
+  applies to [=part-like pseudo-elements=].
+
+
 <h3 id="file-selector-button-pseudo">
 File Selector Button: the ''::file-selector-button'' pseudo-element</h3>