[css-position-3] Clarify writing mode for various positioned layout rules. #5077

Author: fantasai

css-position-3/Overview.bs

@@ -584,6 +584,7 @@ Relative Positioning</h3>
 		<li>
 			If neither is ''top/auto'',
 			the position is over-constrained;
+			(with respect to the [=writing mode=] of its [=containing block=])
 			the [=computed value|computed=] [=CSS/end=] side value is ignored,
 			and its [=used value=] becomes the negation of the [=CSS/start=] side.
 	</ul>
@@ -627,10 +628,11 @@ Sticky positioning</h3>
 	(For this purpose an ''top/auto'' value represents a zero inset.)
 	If this results in a [=sticky view rectangle=] size in any axis
 	less than the size of the [=border box=] of the [=sticky=] box in that axis,
-	then the effective end-edge inset in the affected axis is reduced
+	then the effective [=end=]-edge inset in the affected axis is reduced
 	(possibly becoming negative)
 	to bring the [=sticky view rectangle=]’s size up to
-	the size of the [=border box=] in that axis.
+	the size of the [=border box=] in that axis
+	(where [=end=] is interpreted relative to the [=writing mode=] of the [=containing block=]).
 
 	<div class=example>
 		For example,
@@ -736,7 +738,8 @@ Absolute (and Fixed) Positioning</h3>
 	to bring that size up to zero.
 	In the case that only one inset is ''auto'',
 	that is the <dfn>weaker inset</dfn>;
-	otherwise the [=weaker inset=] is the end-edge inset.
+	otherwise the [=weaker inset=] is the inset of the [=end=] edge
+	(where [=end=] is interpreted relative to the [=writing mode=] of the [=containing block=]).
 
 	Note: Sizing and positioning of the [=absolutely positioned box=]
 	into this <dfn>inset-modified containing block</dfn>
@@ -909,7 +912,7 @@ Auto Margins of Absolutely-Positioned Boxes</h3>
 	and this <var>remaining space</var> is divided among
 	any ''margin/auto'' margins in the relevant axis.
 	However,
-	(all with respect to the [=writing mode=] of the [=containing block=])
+	(all with respect to the [=writing mode=] of the [=containing block=]),
 	if in the [=inline axis=]
 	the <var>remaining space</var> is negative
 	and both margins are ''margin/auto'',
@@ -1654,11 +1657,28 @@ Acknowledgments</h2>
 				is determined as above.</ins></p>
 			</blockquote>
 
-		<li>Aligned resolution of auto margins on absolutely-positioned boxes with [[CSS2]].
-			(<a href="https://github.com/w3c/csswg-drafts/issues/5374">Issue 5374</a>)
+		<li>Aligned resolution of auto margins on positioned boxes with [[CSS2]].
+			(<a href="https://github.com/w3c/csswg-drafts/issues/5374">Issue 5374</a>,
+			 <a href="https://github.com/w3c/csswg-drafts/issues/5077">Issue 5077</a>)
+			<blockquote>
+				<p>If this results in a [=sticky view rectangle=] size in any axis
+				less than the size of the [=border box=] of the [=sticky=] box in that axis,
+				then the effective [=end=]-edge inset in the affected axis is reduced
+				(possibly becoming negative)
+				to bring the [=sticky view rectangle=]’s size up to
+				the size of the [=border box=] in that axis
+				<ins>(where [=end=] is interpreted relative to the [=writing mode=] of the [=containing block=])</ins>.
+			</blockquote>
+			<blockquote>
+				If neither is ''top/auto'',
+				the position is over-constrained;
+				<ins>(with respect to the [=writing mode=] of its [=containing block=])</ins>
+				the [=computed value|computed=] [=CSS/end=] side value is ignored,
+				and its [=used value=] becomes the negation of the [=CSS/start=] side.
+			</blockquote>
 			<blockquote>
 				However,
-				<ins>(all with respect to the [=writing mode=] of the [=containing block=])
+				<ins>(all with respect to the [=writing mode=] of the [=containing block=]),
 				if in the [=inline axis=]</ins>
 				the <var>remaining space</var> is negative
 				and both margins are ''margin/auto'',