[css-anchor-position-1] Specify computed value of 'position-area' w3c#11828

Author: fantasai

css-anchor-position-1/Overview.bs

@@ -573,6 +573,7 @@ Initial: none
 Inherited: no
 Applies to: positioned boxes with a [=default anchor box=]
 Animation type: TBD
+Computed value: the keyword ''position-area/none'' or a pair of keywords, see [[#position-area-computed]]
 </pre>
 
 Most common use-cases of [=anchor positioning=]
@@ -675,7 +676,7 @@ The allowed syntax of a <<position-area>> value is:
 ]
 </pre>
 
-The <<position-area>> value selects a region of the [=position area grid=]
+The <<position-area>> value selects a region of the [=position-area grid=]
 by specifying the rows and columns the region occupies as follows:
 
 <dl dfn-type=value dfn-for="position-area, <position-area>">
@@ -740,6 +741,17 @@ otherwise, it behaves as if the given keyword was repeated.
 (For example, ''position-area/top'' is equivalent to ''top span-all'',
 but ''position-area/center'' is equivalent to ''center center''.)
 
+<h4 id=position-area-computed>
+Computed Value and Serialization of <<position-area>></h4>
+
+The [=computed value=] of a <<position-area>> value is
+the two keywords indicating the selected tracks in each axis,
+with the long (''position-area/block-start'') and short (''position-area/start'') logical keywords
+treated as equivalent.
+It serializes in the order given in the grammar (above),
+with the logical keywords serialized in their short forms
+(e.g. ''start start'' instead of ''block-start inline-start'').
+
 <h4 id=position-area-alignment>
 Area-specific Default Alignment</h4>