[css-cascade-5] Clarify the behavior of layer syntax in @import w3c#6776

Author: mirisuzanne

css-cascade-5/Overview.bs

@@ -146,6 +146,12 @@ Importing Style Sheets: the ''@import'' rule</h2>
 		into its own anonymous [=cascade layer=]
 		or into the named [=cascade layer=].
 
+		The layer is added to the [[#layer-ordering|layer order]]
+		even if the import fails to load the stylesheet,
+		but is subject to any [=import conditions=]
+		(just as if declared by an ''@layer'' rule wrapped
+		in the appropriate [=conditional group rules=]).
+
 	* the optional [<<supports-condition>>|<<declaration>>] and <<media-query-list>>
 		(collectively, the <dfn export>import conditions</dfn>)
 		state the conditions under which it applies.
@@ -1946,6 +1952,9 @@ Non-trivial changes since the <a href="https://www.w3.org/TR/2021/WD-css-cascade
 		(<a href="https://github.com/w3c/csswg-drafts/issues/6193">Issue 6193</a>)
 	* Added [[#layer-apis]] section.
 		(<a href="https://github.com/w3c/csswg-drafts/issues/6576">Issue 6576</a>)
+	* Clarified the behavior of the ''layer'' keyword and ''layer()'' function
+		on ''@import'' rules.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/6776">Issue 6776</a>)
 
 <h3 id="changes-2021-08">
 Changes since the 29 August 2021 Working Draft</h3>