--- a/servo/components/style/properties/helpers/animated_properties.mako.rs
+++ b/servo/components/style/properties/helpers/animated_properties.mako.rs
@@ -83,16 +83,28 @@ impl TransitionProperty {
     pub fn from_declaration(declaration: &PropertyDeclaration) -> Option<Self> {
         match *declaration {
             % for prop in data.longhands:
                 % if prop.animatable:
                     PropertyDeclaration::${prop.camel_case}(..)
                         => Some(TransitionProperty::${prop.camel_case}),
                 % endif
             % endfor
+            PropertyDeclaration::CSSWideKeyword(id, _) |
+            PropertyDeclaration::WithVariables(id, _) => {
+                match id {
+                    % for prop in data.longhands:
+                        % if prop.animatable:
+                            LonghandId::${prop.camel_case} =>
+                                Some(TransitionProperty::${prop.camel_case}),
+                        % endif
+                    % endfor
+                    _ => None,
+                }
+            },
             _ => None,
         }
     }
 }
 
 impl ToCss for TransitionProperty {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result
         where W: fmt::Write,