[css-values-4] Switch vi/vb to use writing mode of element itself. w3c#6873

Author: fantasai

css-values-4/Overview.bs

@@ -2114,7 +2114,7 @@ The Various Viewport-relative Units</h5>
 			[=small viewport size=],
 			and [=dynamic viewport size=]
 			(respectively)
-			in the direction of the root element's inline axis.
+			in the box’s [=inline axis=].
 
 		<dt><dfn lt=vb>vb unit</dfn>
 		<dt><dfn lt=svb>svb unit</dfn>
@@ -2127,7 +2127,7 @@ The Various Viewport-relative Units</h5>
 			[=large viewport size=],
 			and [=dynamic viewport size=]
 			(respectively)
-			in the direction of the root element's block axis.
+			in the box’s [=block axis=].
 
 		<dt><dfn lt="vmin">vmin unit</dfn>
 		<dt><dfn lt="svmin">svmin unit</dfn>
@@ -2171,7 +2171,7 @@ The Various Viewport-relative Units</h5>
 	but can also block critical content (such as toolbars, headers, and footers) in others.
 	It's therefore not entirely clear whether this is the best mapping.
 
-	In situations where there is no root element
+	In situations where there is no element
 	or it hasn't yet been styled
 	(such as when evaluating <a>media queries</a>),
 	the ''*vi'' and ''*vb'' units use the initial value of the 'writing-mode' property
@@ -5191,9 +5191,11 @@ Recent Changes</h3>
 
 	(This is a subset of [[#additions-L3]].)
 
-	Substantial since <a href="https://www.w3.org/TR/2021/WD-css-values-4-20211016/">16 October 2021 WD</a>:
+	Substantial changes since <a href="https://www.w3.org/TR/2021/WD-css-values-4-20211016/">16 October 2021 WD</a>:
 
 	<ul>
+		<li>Switched ''*vi'' and ''*vb'' units to resolve against the computed [=writing mode=] of the element itself.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/6873">Issue 6873</a>)
 		<li>Added [[#url-process]] to define integration with CORS, etc.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/562">Issue 562</a>)
 		<li>Fixed the inverted assignment of [=viewport-percentage length=] behaviors