diff --git a/components/style/gecko/generated/gecko_pseudo_element_helper.rs b/components/style/gecko/generated/gecko_pseudo_element_helper.rs
index 37b27f42e19..987580028a2 100644
--- a/components/style/gecko/generated/gecko_pseudo_element_helper.rs
+++ b/components/style/gecko/generated/gecko_pseudo_element_helper.rs
@@ -37,6 +37,9 @@
     pseudo_element!(":backdrop",
                     atom!(":backdrop"),
                     false);
+    pseudo_element!(":cue",
+                    atom!(":cue"),
+                    false);
     pseudo_element!(":first-letter",
                     atom!(":first-letter"),
                     false);
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index acef8183eee..1b770ff4bfe 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -188,6 +188,7 @@ use gecko_bindings::structs::Loader;
 use gecko_bindings::structs::ServoStyleSheet;
 use gecko_bindings::structs::EffectCompositor_CascadeLevel;
 use gecko_bindings::structs::UpdateAnimationsTasks;
+use gecko_bindings::structs::LengthParsingMode;
 pub type nsTArrayBorrowed_uintptr_t<'a> = &'a mut ::gecko_bindings::structs::nsTArray<usize>;
 pub type ServoCssRulesStrong = ::gecko_bindings::sugar::ownership::Strong<ServoCssRules>;
 pub type ServoCssRulesBorrowed<'a> = &'a ServoCssRules;
@@ -1817,8 +1818,9 @@ extern "C" {
                                               property: *const nsACString,
                                               value: *const nsACString,
                                               is_important: bool,
-                                              data: *mut RawGeckoURLExtraData)
-     -> bool;
+                                              data: *mut RawGeckoURLExtraData,
+                                              length_parsing_mode:
+                                                  LengthParsingMode) -> bool;
 }
 extern "C" {
     pub fn Servo_DeclarationBlock_SetPropertyById(declarations:
@@ -1827,7 +1829,9 @@ extern "C" {
                                                   value: *const nsACString,
                                                   is_important: bool,
                                                   data:
-                                                      *mut RawGeckoURLExtraData)
+                                                      *mut RawGeckoURLExtraData,
+                                                  length_parsing_mode:
+                                                      LengthParsingMode)
      -> bool;
 }
 extern "C" {
diff --git a/components/style/gecko_bindings/structs_debug.rs b/components/style/gecko_bindings/structs_debug.rs
index 39ad1af13c2..ae04ddfe363 100644
--- a/components/style/gecko_bindings/structs_debug.rs
+++ b/components/style/gecko_bindings/structs_debug.rs
@@ -6126,6 +6126,13 @@ pub mod root {
                         "Alignment of field: " , stringify ! ( URLExtraData )
                         , "::" , stringify ! ( mPrincipal ) ));
         }
+        pub mod dmd {
+            #[allow(unused_imports)]
+            use self::super::super::super::root;
+        }
+        #[repr(C)]
+        #[derive(Debug, Copy, Clone)]
+        pub struct JSONWriteFunc([u8; 0]);
         #[repr(u32)]
         #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
         pub enum ArenaObjectID {
@@ -6653,6 +6660,9 @@ pub mod root {
                   root::mozilla::UpdateAnimationsTasks =
             8;
         pub type UpdateAnimationsTasks = u8;
+        #[repr(i32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LengthParsingMode { Default = 0, SVG = 1, }
         pub type CSSPseudoElementTypeBase = u8;
         pub const CSSPseudoElementType_InheritingAnonBox:
                   root::mozilla::CSSPseudoElementType =
diff --git a/components/style/gecko_bindings/structs_release.rs b/components/style/gecko_bindings/structs_release.rs
index e3dfdd704b4..4768b429165 100644
--- a/components/style/gecko_bindings/structs_release.rs
+++ b/components/style/gecko_bindings/structs_release.rs
@@ -6029,6 +6029,13 @@ pub mod root {
                         "Alignment of field: " , stringify ! ( URLExtraData )
                         , "::" , stringify ! ( mPrincipal ) ));
         }
+        pub mod dmd {
+            #[allow(unused_imports)]
+            use self::super::super::super::root;
+        }
+        #[repr(C)]
+        #[derive(Debug, Copy, Clone)]
+        pub struct JSONWriteFunc([u8; 0]);
         #[repr(u32)]
         #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
         pub enum ArenaObjectID {
@@ -6556,6 +6563,9 @@ pub mod root {
                   root::mozilla::UpdateAnimationsTasks =
             8;
         pub type UpdateAnimationsTasks = u8;
+        #[repr(i32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum LengthParsingMode { Default = 0, SVG = 1, }
         pub type CSSPseudoElementTypeBase = u8;
         pub const CSSPseudoElementType_InheritingAnonBox:
                   root::mozilla::CSSPseudoElementType =
diff --git a/components/style/gecko_string_cache/atom_macro.rs b/components/style/gecko_string_cache/atom_macro.rs
index 33e9dc034f0..6d99ed66fb1 100644
--- a/components/style/gecko_string_cache/atom_macro.rs
+++ b/components/style/gecko_string_cache/atom_macro.rs
@@ -4790,6 +4790,8 @@ cfg_if! {
             pub static nsCSSPseudoElements_before: *mut nsICSSPseudoElement;
             #[link_name = "_ZN19nsCSSPseudoElements8backdropE"]
             pub static nsCSSPseudoElements_backdrop: *mut nsICSSPseudoElement;
+            #[link_name = "_ZN19nsCSSPseudoElements3cueE"]
+            pub static nsCSSPseudoElements_cue: *mut nsICSSPseudoElement;
             #[link_name = "_ZN19nsCSSPseudoElements11firstLetterE"]
             pub static nsCSSPseudoElements_firstLetter: *mut nsICSSPseudoElement;
             #[link_name = "_ZN19nsCSSPseudoElements9firstLineE"]
@@ -9721,6 +9723,8 @@ cfg_if! {
             pub static nsCSSPseudoElements_before: *mut nsICSSPseudoElement;
             #[link_name = "?backdrop@nsCSSPseudoElements@@2PEAVnsICSSPseudoElement@@EA"]
             pub static nsCSSPseudoElements_backdrop: *mut nsICSSPseudoElement;
+            #[link_name = "?cue@nsCSSPseudoElements@@2PEAVnsICSSPseudoElement@@EA"]
+            pub static nsCSSPseudoElements_cue: *mut nsICSSPseudoElement;
             #[link_name = "?firstLetter@nsCSSPseudoElements@@2PEAVnsICSSPseudoElement@@EA"]
             pub static nsCSSPseudoElements_firstLetter: *mut nsICSSPseudoElement;
             #[link_name = "?firstLine@nsCSSPseudoElements@@2PEAVnsICSSPseudoElement@@EA"]
@@ -14652,6 +14656,8 @@ cfg_if! {
             pub static nsCSSPseudoElements_before: *mut nsICSSPseudoElement;
             #[link_name = "\x01?backdrop@nsCSSPseudoElements@@2PAVnsICSSPseudoElement@@A"]
             pub static nsCSSPseudoElements_backdrop: *mut nsICSSPseudoElement;
+            #[link_name = "\x01?cue@nsCSSPseudoElements@@2PAVnsICSSPseudoElement@@A"]
+            pub static nsCSSPseudoElements_cue: *mut nsICSSPseudoElement;
             #[link_name = "\x01?firstLetter@nsCSSPseudoElements@@2PAVnsICSSPseudoElement@@A"]
             pub static nsCSSPseudoElements_firstLetter: *mut nsICSSPseudoElement;
             #[link_name = "\x01?firstLine@nsCSSPseudoElements@@2PAVnsICSSPseudoElement@@A"]
@@ -19586,6 +19592,8 @@ macro_rules! atom {
   { unsafe { $crate::string_cache::atom_macro::atom_from_static($crate::string_cache::atom_macro::nsCSSPseudoElements_before as *mut _) } };
 (":backdrop") =>
   { unsafe { $crate::string_cache::atom_macro::atom_from_static($crate::string_cache::atom_macro::nsCSSPseudoElements_backdrop as *mut _) } };
+(":cue") =>
+  { unsafe { $crate::string_cache::atom_macro::atom_from_static($crate::string_cache::atom_macro::nsCSSPseudoElements_cue as *mut _) } };
 (":first-letter") =>
   { unsafe { $crate::string_cache::atom_macro::atom_from_static($crate::string_cache::atom_macro::nsCSSPseudoElements_firstLetter as *mut _) } };
 (":first-line") =>