[css-conditional-5] Made last @supports-condition win #12973

Author: SebastianZ

css-conditional-5/Overview.bs

@@ -1778,7 +1778,8 @@ improving maintainability and readability.
 
 	Once defined, the named supports condition can be used in subsequent ''@supports'' or ''@when'' conditions.
 
-	Multiple ''@supports-condition'' rules with the same name in a style sheet are invalid and must be ignored.
+	If multiple ''@supports-condition'' rules are defined with the same name,
+	the last one in document order wins, and all preceding ones are ignored.
 
 	<div class="example">
 		For example, we can define a supports query checking multiple properties at once: