[css-conditional-3] explicit CSS parse, w3c#3173

Author: svgeesus

css-conditional-3/Overview.bs

@@ -525,8 +525,9 @@ interface CSSConditionRule : CSSGroupingRule {
 
     <ol>
       <li>Trim the given value of white space.
-      <li>If the given value matches the grammar of the
-        appropriate condition production for the given rule,
+      <li>If the given value [=CSS/parses=]
+        as the appropriate condition grammar for the given rule
+        (such as <<supports-condition>> for ''@supports'', etc),
         replace the associated CSS condition with the given value.
       <li>Otherwise, do nothing.
     </ol>