[css-align-3] Make text clearer for sizing of abspos double-auto blocks. w3c#1432

Author: tabatkins

css-align-3/Overview.bs

@@ -1706,7 +1706,7 @@ Effects on Sizing of Absolutely Positioned Boxes with Static-Position Insets</h3
 	the <a>available space</a> for calculating the <a>inline size</a>
 	is also affected by alignment.
 
-	In [[CSS2]], this is keyed off of the the 'direction' property
+	Note: In [[CSS2]], the [=available space=] is keyed off of the the 'direction' property
 	of the <a>static-position containing block</a>.
 	(See <a href="https://www.w3.org/TR/CSS2/visudet.html#abs-non-replaced-width">CSS2&sect;10.3.7</a>
 	and <a href="https://www.w3.org/TR/CSS2/visudet.html#abs-replaced-width">CSS2&sect;10.3.8</a>.)
@@ -1715,18 +1715,21 @@ Effects on Sizing of Absolutely Positioned Boxes with Static-Position Insets</h3
 	to the corresponding edge of the <a>static position rectangle</a>
 	and the other to the corresponding edge of the <a>containing block</a>
 	(i.e. set the inset to zero).
-
 	Just as the <a>self-alignment properties</a>
-	replace the <a>containing block</a>’s 'direction' for placement,
-	they also replace this lookup for sizing.
+	replace the <a>containing block</a>’s 'direction' lookup for placement,
+	they also replace this lookup for sizing,
+	as specified here.
+
 	Thus,
 	when interpreting the rules in
 	<a href="https://www.w3.org/TR/CSS2/visudet.html#abs-non-replaced-width">CSS2&sect;10.3.7</a>
 	and <a href="https://www.w3.org/TR/CSS2/visudet.html#abs-replaced-width">CSS2&sect;10.3.8</a>,
 	wherever the 'direction' property of the <a>static-position containing block</a> is referenced,
 	instead reference the value of the 'align-self' or 'justify-self' property
 	(whichever is defined to apply to the relevant axis),
-	treating ''justify-self/normal'' as ''start''
+	treating left-equivalent alignment as defined for ''ltr''
+	and right-equivalent alignment as defined for ''rtl''.
+	Treat ''justify-self/normal'' as ''start''
 	and any <a>distributed alignment</a> value as its <a>fallback alignment</a>.
 
 	In the case of ''justify-self/center'' alignment,
@@ -1747,7 +1750,8 @@ Effects on Sizing of Absolutely Positioned Boxes with Static-Position Insets</h3
 			Instead of always sizing
 			within the available space between
 			the <a>inline-start</a> <a>static position</a>
-			and the <a>inline-end</a> <a>containing block</a> edge,
+			and the <a>inline-end</a> <a>containing block</a> edge
+			as specified in [[CSS2]],
 			an absolutely-positioned element with ''left/auto'' insets
 			will be sized with reference to
 			the <a>static position rectangle</a>’s edge(s)
@@ -1777,6 +1781,10 @@ Effects on Sizing of Absolutely Positioned Boxes with Static-Position Insets</h3
 	with <a>stretch-fit sizing</a> (consuming all of the <a>available space</a>).
 	This is an independent effect from the available space adjustment here.
 
+	Note: This only affect how [=available space=] is calculated
+	for sizing the absolutely-positioned box;
+	its alignment is as specified in previous sections.
+
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