consumption of CSS Variable

org/w3c/css/parser/CssFouffa.java

@@ -587,7 +587,9 @@ public CssProperty handleDeclaration(String property, CssExpression expression,
         if (Util.onDebug) {
             System.err.println("Creating " + property + ": " + expression);
         }
-
+        if (property.startsWith("--")) {
+            // css variable
+        }
         final CssValue lastValue = expression.getLastValue();
 
         if (allowBackslash9Hack() && lastValue != null && lastValue.hasBackslash9Hack()) {

org/w3c/css/parser/CssPropertyFactory.java

@@ -253,6 +253,10 @@ public synchronized CssProperty createProperty(ApplContext ac, AtRule atRule, St
             throw new WarningParamException("vendor-extension", expression.toStringFromStart());
         }
 
+        if (expression.hasCssVariable()) {
+            throw new WarningParamException("css-variable", expression.toStringFromStart());
+        }
+
         if (ac.getTreatCssHacksAsWarnings() && expression.hasCssHack()) {
             throw new WarningParamException("css-hack", expression.toStringFromStart());
         }