diff --git a/components/style/animation.rs b/components/style/animation.rs
index 2dabb608d99..1545cac72f8 100644
--- a/components/style/animation.rs
+++ b/components/style/animation.rs
@@ -430,6 +430,7 @@ fn compute_style_for_animation_step(context: &SharedStyleContext,
                                                /* is_root = */ false,
                                                iter,
                                                previous_style,
+                                               &context.default_computed_values,
                                                /* cascade_info = */ None,
                                                context.error_reporter.clone(),
                                                /* Metrics provider */ None,
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index 0a94d146cd7..03f51a130ca 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -1248,7 +1248,8 @@ extern "C" {
      -> RawServoDeclarationBlockStrong;
 }
 extern "C" {
-    pub fn Servo_RestyleWithAddedDeclaration(declarations:
+    pub fn Servo_RestyleWithAddedDeclaration(set: RawServoStyleSetBorrowed,
+                                             declarations:
                                                  RawServoDeclarationBlockBorrowed,
                                              previous_style:
                                                  ServoComputedValuesBorrowed)
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 66a8e158582..d5d068060bf 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -1746,6 +1746,7 @@ pub fn cascade(viewport_size: Size2D<Au>,
                        is_root_element,
                        iter_declarations,
                        inherited_style,
+                       default_style,
                        cascade_info,
                        error_reporter,
                        None,
@@ -1758,6 +1759,7 @@ pub fn apply_declarations<'a, F, I>(viewport_size: Size2D<Au>,
                                     is_root_element: bool,
                                     iter_declarations: F,
                                     inherited_style: &ComputedValues,
+                                    default_style: &Arc<ComputedValues>,
                                     mut cascade_info: Option<<&mut CascadeInfo>,
                                     mut error_reporter: StdBox<ParseErrorReporter + Send>,
                                     font_metrics_provider: Option<<&FontMetricsProvider>,
@@ -1784,8 +1786,6 @@ pub fn apply_declarations<'a, F, I>(viewport_size: Size2D<Au>,
         ::custom_properties::finish_cascade(
             custom_properties, &inherited_custom_properties);
 
-    let initial_values = ComputedValues::initial_values();
-
     let starting_style = if !flags.contains(INHERIT_ALL) {
         ComputedValues::new(custom_properties,
                             flags.contains(SHAREABLE),
@@ -1795,7 +1795,7 @@ pub fn apply_declarations<'a, F, I>(viewport_size: Size2D<Au>,
                                 % if style_struct.inherited:
                                     inherited_style.clone_${style_struct.name_lower}(),
                                 % else:
-                                    initial_values.clone_${style_struct.name_lower}(),
+                                    default_style.clone_${style_struct.name_lower}(),
                                 % endif
                             % endfor
                             )
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 9c947fc73f7..a0be6d60f80 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -170,7 +170,8 @@ pub extern "C" fn Servo_TraverseSubtree(root: RawGeckoElementBorrowed,
 }
 
 #[no_mangle]
-pub extern "C" fn Servo_RestyleWithAddedDeclaration(declarations: RawServoDeclarationBlockBorrowed,
+pub extern "C" fn Servo_RestyleWithAddedDeclaration(raw_data: RawServoStyleSetBorrowed,
+                                                    declarations: RawServoDeclarationBlockBorrowed,
                                                     previous_style: ServoComputedValuesBorrowed)
   -> ServoComputedValuesStrong
 {
@@ -183,11 +184,14 @@ pub extern "C" fn Servo_RestyleWithAddedDeclaration(declarations: RawServoDeclar
         guard.declarations.iter().rev().map(|&(ref decl, _importance)| decl)
     };
 
+    let data = PerDocumentStyleData::from_ffi(raw_data).borrow();
+
     // FIXME (bug 1303229): Use the actual viewport size here
     let computed = apply_declarations(Size2D::new(Au(0), Au(0)),
                                       /* is_root_element = */ false,
                                       declarations,
                                       previous_style,
+                                      &data.default_computed_values,
                                       None,
                                       Box::new(StdoutErrorReporter),
                                       None,