diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index 2f8a6aa9c34..9d355444e27 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -1317,8 +1317,11 @@ extern "C" {
                                                          nsCSSPropertyID);
 }
 extern "C" {
-    pub fn Servo_CSSSupports(name: *const nsACString_internal,
-                             value: *const nsACString_internal) -> bool;
+    pub fn Servo_CSSSupports2(name: *const nsACString_internal,
+                              value: *const nsACString_internal) -> bool;
+}
+extern "C" {
+    pub fn Servo_CSSSupports(cond: *const nsACString_internal) -> bool;
 }
 extern "C" {
     pub fn Servo_ComputedValues_GetForAnonymousBox(parent_style_or_null:
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 166ac850be2..70ec377cce7 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -64,6 +64,7 @@ use style::sequential;
 use style::string_cache::Atom;
 use style::stylesheets::{CssRule, CssRules, Origin, Stylesheet, StyleRule, ImportRule};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
+use style::supports::parse_condition_or_declaration;
 use style::thread_state;
 use style::timer::Timer;
 use style::traversal::{resolve_style, DomTraversal};
@@ -902,7 +903,7 @@ pub extern "C" fn Servo_DeclarationBlock_RemovePropertyById(declarations: RawSer
 }
 
 #[no_mangle]
-pub extern "C" fn Servo_CSSSupports(property: *const nsACString, value: *const nsACString) -> bool {
+pub extern "C" fn Servo_CSSSupports2(property: *const nsACString, value: *const nsACString) -> bool {
     let property = unsafe { property.as_ref().unwrap().as_str_unchecked() };
     let id =  if let Ok(id) = PropertyId::parse(property.into()) {
         id
@@ -920,6 +921,20 @@ pub extern "C" fn Servo_CSSSupports(property: *const nsACString, value: *const n
     }
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_CSSSupports(cond: *const nsACString) -> bool {
+    let condition = unsafe { cond.as_ref().unwrap().as_str_unchecked() };
+    let mut input = Parser::new(&condition);
+    let cond = parse_condition_or_declaration(&mut input);
+    if let Ok(cond) = cond {
+        let url = ServoUrl::parse("about:blank").unwrap();
+        let context = ParserContext::new_for_cssom(&url);
+        cond.eval(&context)
+    } else {
+        false
+    }
+}
+
 /// Only safe to call on the main thread, with exclusive access to the element and
 /// its ancestors.
 unsafe fn maybe_restyle<'a>(data: &'a mut AtomicRefMut<ElementData>, element: GeckoElement)