diff --git a/patches/components/script/dom/document/document.rs.patch b/patches/components/script/dom/document/document.rs.patch
index 628baeb..8ebd8a6 100644
--- a/patches/components/script/dom/document/document.rs.patch
+++ b/patches/components/script/dom/document/document.rs.patch
@@ -95,7 +95,26 @@
      /// All websockets created that are associated with this document.
      websockets: DOMTracker<WebSocket>,
 
-@@ -707,6 +730,11 @@
+@@ -667,6 +690,18 @@
+     /// Reflect the value of that preferences to prevent paying the cost of a RwLock access.
+     layout_animations_test_enabled: bool,
+
++    /// Whether the frame in progress has pinned the animation timeline.
++    ///
++    /// A frame must hold one timestamp so that every animation it samples agrees,
++    /// which is what the pin protects. But reflows also happen *outside* a frame, like
++    /// script reading `offsetWidth`, or a timer callback that touches style and a
++    /// `ReflowRequest` carries the timeline value that stylo stamps onto any
++    /// transition the restyle starts. Unpinned, those reflows must advance the
++    /// clock first: otherwise the stamp is however old the last frame was, and on
++    /// an idle document a transition born that stale is already past its end and is
++    /// retired on its first tick instead of running.
++    animation_timeline_pinned_for_frame: Cell<bool>,
++
+     /// <https://w3c.github.io/editing/docs/execCommand/#state-override>
+     #[no_trace]
+     state_override: DomRefCell<FxHashMap<CommandName, bool>>,
+@@ -707,6 +742,11 @@
 
      /// <https://html.spec.whatwg.org/multipage/#doc-history>
      history: MutNullableDom<History>,
@@ -107,7 +126,7 @@
  }
 
  impl Document {
-@@ -891,6 +919,68 @@
+@@ -891,6 +931,68 @@
          self.dirty_root.take()
      }
 
@@ -176,7 +195,7 @@
      #[inline]
      pub(crate) fn loader(&self) -> Ref<'_, DocumentLoader> {
          self.loader.borrow()
-@@ -962,6 +1052,12 @@
+@@ -962,6 +1064,12 @@
 
          // Set the document's activity level, reflow if necessary, and suspend or resume timers.
          self.activity.set(activity);
@@ -189,7 +208,7 @@
          let media = ServoMedia::get();
          let pipeline_id = self.window().pipeline_id();
          let client_context_id =
-@@ -975,6 +1071,7 @@
+@@ -975,6 +1083,7 @@
 
          self.title_changed();
          self.notify_embedder_favicon();
@@ -197,7 +216,7 @@
          self.dirty_all_nodes(cx.no_gc());
          self.window().resume(cx);
          media.resume(&client_context_id);
-@@ -1362,6 +1459,9 @@
+@@ -1362,6 +1471,9 @@
                          LoadStatus::Started,
                      ));
                      self.send_to_embedder(EmbedderMsg::Status(self.webview_id(), None));
@@ -207,7 +226,7 @@
                  }
              },
              DocumentReadyState::Complete => {
-@@ -1370,6 +1470,9 @@
+@@ -1370,6 +1482,9 @@
                          self.webview_id(),
                          LoadStatus::Complete,
                      ));
@@ -217,7 +236,7 @@
                  }
                  update_with_current_instant(&self.navigation_timing.dom_complete);
              },
-@@ -1450,7 +1553,13 @@
+@@ -1450,7 +1565,13 @@
          let window = self.window();
          if window.is_top_level() {
              let title = self.title().map(String::from);
@@ -232,7 +251,7 @@
          }
      }
 
-@@ -1459,6 +1568,18 @@
+@@ -1459,6 +1580,18 @@
          window.send_to_embedder(msg);
      }
 
@@ -251,7 +270,7 @@
      pub(crate) fn dirty_all_nodes(&self, no_gc: &NoGC) {
          let root = match self.GetDocumentElement() {
              Some(root) => root,
-@@ -2907,6 +3028,17 @@
+@@ -2907,6 +3040,17 @@
          self.iframes.borrow_mut()
      }
 
@@ -269,7 +288,7 @@
      pub(crate) fn set_navigation_start(&self, navigation_start: CrossProcessInstant) {
          self.interactive_time
              .borrow_mut()
-@@ -3187,6 +3319,60 @@
+@@ -3187,6 +3331,60 @@
              .push(Dom::from_ref(resize_observer));
      }
 
@@ -330,7 +349,7 @@
      /// <https://drafts.csswg.org/resize-observer/#gather-active-observations-h>
      /// <https://drafts.csswg.org/resize-observer/#has-active-resize-observations>
      pub(crate) fn gather_active_resize_observations_at_depth(
-@@ -3764,6 +3950,7 @@
+@@ -3764,6 +3962,7 @@
              anchors: Default::default(),
              applets: Default::default(),
              iframes: RefCell::new(IFrameCollection::new()),
@@ -338,7 +357,7 @@
              shared_style_locks,
              stylesheets: DomRefCell::new(DocumentStylesheetSet::new()),
              stylesheet_list: MutNullableDom::new(None),
-@@ -3823,6 +4010,8 @@
+@@ -3823,6 +4022,8 @@
              dirty_root: Default::default(),
              declarative_refresh: Default::default(),
              resize_observers: Default::default(),
@@ -347,7 +366,7 @@
              fonts: Default::default(),
              visibility_state: Cell::new(DocumentVisibilityState::Hidden),
              status_code,
-@@ -3844,6 +4033,7 @@
+@@ -3844,10 +4045,12 @@
              active_sandboxing_flag_set: Cell::new(creation_sandboxing_flag_set),
              creation_sandboxing_flag_set: Cell::new(creation_sandboxing_flag_set),
              favicon: RefCell::new(None),
@@ -355,7 +374,12 @@
              websockets: DOMTracker::new(),
              details_name_groups: Default::default(),
              protocol_handler_automation_mode: Default::default(),
-@@ -3864,6 +4054,7 @@
+             layout_animations_test_enabled: pref!(layout_animations_test_enabled),
++            animation_timeline_pinned_for_frame: Cell::new(false),
+             state_override: Default::default(),
+             value_override: Default::default(),
+             default_single_line_container_name: Default::default(),
+@@ -3864,6 +4067,7 @@
              )),
              image_cache,
              history: Default::default(),
@@ -363,7 +387,54 @@
          }
      }
 
-@@ -4892,6 +5083,36 @@
+@@ -4615,6 +4819,33 @@
+             .mark_animating_nodes_as_dirty(current_timeline_value);
+     }
+
++    /// Sample the clock into the animation timeline, unless a test owns it (see
++    /// `advance_animation_timeline_for_testing`).
++    fn advance_animation_timeline(&self) {
++        if !self.layout_animations_test_enabled {
++            self.timeline.update(self.window());
++        }
++    }
++
++    /// Advance the timeline unless the frame in progress has already pinned it.
++    pub(crate) fn ensure_animation_timeline_is_current(&self) {
++        if !self.animation_timeline_pinned_for_frame.get() {
++            self.advance_animation_timeline();
++        }
++    }
++
++    /// Pin the timeline for the frame now starting its animation steps, so every
++    /// animation it samples and its own reflow share one timestamp.
++    pub(crate) fn pin_animation_timeline_for_frame(&self) {
++        self.animation_timeline_pinned_for_frame.set(true);
++    }
++
++    /// Release the pin once a rendering update has finished with this document, so
++    /// a reflow forced from a later task gets a fresh timestamp.
++    pub(crate) fn release_animation_timeline_for_frame(&self) {
++        self.animation_timeline_pinned_for_frame.set(false);
++    }
++
+     pub(crate) fn current_animation_timeline_value(&self) -> f64 {
+         self.timeline
+             .upcast::<AnimationTimeline>()
+@@ -4643,10 +4874,8 @@
+
+     /// An implementation of <https://drafts.csswg.org/web-animations-1/#update-animations-and-send-events>.
+     pub(crate) fn update_animations_and_send_events(&self, cx: &mut CurrentRealm) {
+-        // Only update the time if it isn't being managed by a test.
+-        if !self.layout_animations_test_enabled {
+-            self.timeline.update(self.window());
+-        }
++        self.advance_animation_timeline();
++        self.pin_animation_timeline_for_frame();
+
+         // > 1. Update the current time of all timelines associated with doc passing now
+         // > as the timestamp.
+@@ -4892,6 +5121,36 @@
 
      pub(crate) fn notify_embedder_favicon(&self) {
          if let Some(ref image) = *self.favicon.borrow() {
@@ -400,7 +471,7 @@
              self.send_to_embedder(EmbedderMsg::NewFavicon(self.webview_id(), image.clone()));
          }
      }
-@@ -4970,6 +5191,30 @@
+@@ -4970,6 +5229,30 @@
      pub(crate) fn set_iframe_load_in_progress(&self, value: bool) {
          self.iframe_load_in_progress.set(value)
      }
diff --git a/patches/components/script/dom/window/window.rs.patch b/patches/components/script/dom/window/window.rs.patch
index bec6f36..c7ca2a7 100644
--- a/patches/components/script/dom/window/window.rs.patch
+++ b/patches/components/script/dom/window/window.rs.patch
@@ -143,7 +143,18 @@
      /// <https://developer.mozilla.org/en-US/docs/Web/API/Window/screen>
      fn Screen(&self, cx: &mut JSContext) -> DomRoot<Screen> {
          self.screen.or_init(|| Screen::new(cx, self))
-@@ -3235,9 +3289,33 @@
+@@ -2717,6 +2771,10 @@
+             accessibility_damage = Some(accessibility_data.drain_pending_accessibility_damage());
+         }
+
++        // Any transition this reflow's restyle starts is stamped with the timeline
++        // value carried below, so make sure it isn't a previous frame's.
++        document.ensure_animation_timeline_is_current();
++
+         // Send new document and relevant styles to layout.
+         let reflow = ReflowRequest {
+             document: document.upcast::<Node>().to_trusted_node_address(),
+@@ -3235,9 +3293,33 @@
          &self,
          input_event: &ConstellationInputEvent,
      ) -> Option<HitTestResult> {
@@ -180,7 +191,7 @@
      }
 
      #[expect(unsafe_code)]
-@@ -3256,8 +3334,39 @@
+@@ -3256,8 +3338,39 @@
          // SAFETY: This is safe because `Window::query_elements_from_point` has ensured that
          // layout has run and any OpaqueNodes that no longer refer to real nodes are gone.
          let address = UntrustedNodeAddress(result.node.0 as *const c_void);
@@ -221,7 +232,7 @@
              cursor: result.cursor,
              point_in_node: result.point_in_target,
              point_in_frame,
-@@ -3628,17 +3737,19 @@
+@@ -3628,17 +3741,19 @@
      }
 
      pub(crate) fn send_to_embedder(&self, msg: EmbedderMsg) {
@@ -247,7 +258,7 @@
      }
 
      #[cfg(feature = "webxr")]
-@@ -3858,6 +3969,8 @@
+@@ -3858,6 +3973,8 @@
          player_context: WindowGLContext,
          #[cfg(feature = "webgpu")] gpu_id_hub: Arc<IdentityHub>,
          inherited_secure_context: Option<bool>,
@@ -256,7 +267,7 @@
          theme: Theme,
          weak_script_thread: Weak<ScriptThread>,
      ) -> DomRoot<Self> {
-@@ -3882,6 +3995,8 @@
+@@ -3882,6 +3999,8 @@
                  gpu_id_hub,
                  inherited_secure_context,
                  unminify_js,
@@ -265,7 +276,7 @@
                  Some(font_context),
              ),
              caches: Default::default(),
-@@ -4152,3 +4267,114 @@
+@@ -4152,3 +4271,114 @@
          Window::origin(self)
      }
  }
diff --git a/patches/components/script/script_thread.rs.patch b/patches/components/script/script_thread.rs.patch
index 80b9f86..1f5bf9a 100644
--- a/patches/components/script/script_thread.rs.patch
+++ b/patches/components/script/script_thread.rs.patch
@@ -57,7 +57,39 @@
  use crate::dom::servoparser::{ParserContext, ServoParser};
  use crate::dom::types::DebuggerGlobalScope;
  #[cfg(feature = "webgpu")]
-@@ -1832,6 +1840,14 @@
+@@ -1293,18 +1301,22 @@
+             // Unspecified, but necessary: Any of the previous callbacks may have put the
+             // document into a render-blocked state. If that's the case, then abort the
+             // rendering process now.
+-            if document.is_render_blocked() {
+-                continue;
+-            }
++            if !document.is_render_blocked() {
++                // > Step 22: For each doc of docs, update the rendering or user interface of
++                // > doc and its node navigable to reflect the current state.
++                if document.update_the_rendering(cx).0.needs_frame() {
++                    painters_generating_frames.insert(document.webview_id().into());
++                }
+
+-            // > Step 22: For each doc of docs, update the rendering or user interface of
+-            // > doc and its node navigable to reflect the current state.
+-            if document.update_the_rendering(cx).0.needs_frame() {
+-                painters_generating_frames.insert(document.webview_id().into());
++                // TODO: Process top layer removals according to
++                // https://drafts.csswg.org/css-position-4/#process-top-layer-removals.
+             }
+
+-            // TODO: Process top layer removals according to
+-            // https://drafts.csswg.org/css-position-4/#process-top-layer-removals.
++            // Unconditional, and nested above rather than `continue`d past, so that
++            // every way out of this document's frame releases the pin. Leaving it
++            // set would make the next out-of-frame reflow reuse this frame's
++            // timestamp - see `animation_timeline_pinned_for_frame`.
++            document.release_animation_timeline_for_frame();
+         }
+
+         let should_generate_frame = !painters_generating_frames.is_empty();
+@@ -1832,6 +1844,14 @@
              ScriptThreadMessage::GetDocumentOrigin(pipeline_id, result_sender) => {
                  self.handle_get_document_origin(pipeline_id, result_sender);
              },
@@ -72,7 +104,7 @@
              ScriptThreadMessage::GetTitle(pipeline_id) => self.handle_get_title_msg(pipeline_id),
              ScriptThreadMessage::SetDocumentActivity(pipeline_id, activity) => {
                  self.handle_set_document_activity_msg(cx, pipeline_id, activity)
-@@ -1997,12 +2013,47 @@
+@@ -1997,11 +2017,46 @@
                  self.handle_refresh_cursor(pipeline_id);
              },
              ScriptThreadMessage::PreferencesUpdated(updates) => {
@@ -96,7 +128,7 @@
 +
 +                // Dispatch preferencechanged events to all Embedder instances
 +                self.dispatch_preference_changed_to_embedders(cx, &updates);
-             },
++            },
 +            ScriptThreadMessage::ShowTaskChooser(
 +                request_id,
 +                task_name,
@@ -120,11 +152,10 @@
 +            ScriptThreadMessage::TaskProvidersUpdate(request_id, providers_json) => {
 +                // Dispatch an embedder event to update the chooser with remote providers.
 +                self.dispatch_task_providers_update(cx, &request_id, &providers_json);
-+            },
+             },
              ScriptThreadMessage::ForwardKeyboardScroll(pipeline_id, scroll) => {
                  if let Some(document) = self.documents.borrow().find_document(pipeline_id) {
-                     document.event_handler().do_keyboard_scroll(cx, scroll);
-@@ -2034,6 +2085,52 @@
+@@ -2034,6 +2089,52 @@
              ScriptThreadMessage::TriggerGarbageCollection => unsafe {
                  JS_GC(cx, GCReason::API);
              },
@@ -177,7 +208,7 @@
          }
      }
 
-@@ -3097,16 +3194,32 @@
+@@ -3097,16 +3198,32 @@
          reason: UpdatePipelineIdReason,
          cx: &mut js::context::JSContext,
      ) {
@@ -190,15 +221,13 @@
              .borrow()
              .find_iframe(parent_pipeline_id, browsing_context_id);
 -        let Some(frame_element) = frame_element else {
--            return;
 +        let webview = if iframe.is_none() {
 +            self.documents
 +                .borrow()
 +                .find_webview(parent_pipeline_id, browsing_context_id)
 +        } else {
 +            None
-         };
--        if !frame_element.update_pipeline_id(new_pipeline_id, reason, cx) {
++        };
 +        let is_embedded_webview = webview.is_some();
 +
 +        let updated = if let Some(frame_element) = &iframe {
@@ -208,13 +237,15 @@
 +        } else {
              return;
          };
+-        if !frame_element.update_pipeline_id(new_pipeline_id, reason, cx) {
 +        if !updated {
-+            return;
+             return;
+-        };
 +        }
 
          let Some(window) = self.documents.borrow().find_window(new_pipeline_id) else {
              return;
-@@ -3125,6 +3238,7 @@
+@@ -3125,6 +3242,7 @@
              // is no need to pass along existing opener information that
              // will be discarded.
              None,
@@ -222,7 +253,7 @@
          );
      }
 
-@@ -3416,6 +3530,212 @@
+@@ -3416,6 +3534,212 @@
          }
      }
 
@@ -435,7 +466,7 @@
      fn ask_constellation_for_top_level_info(
          &self,
          sender_webview_id: WebViewId,
-@@ -3528,7 +3848,13 @@
+@@ -3528,7 +3852,13 @@
              self.senders.pipeline_to_embedder_sender.clone(),
              self.senders.constellation_sender.clone(),
              incomplete.pipeline_id,
@@ -450,7 +481,7 @@
              incomplete.viewport_details,
              origin.clone(),
              final_url.clone(),
-@@ -3550,6 +3876,8 @@
+@@ -3550,6 +3880,8 @@
              #[cfg(feature = "webgpu")]
              self.gpu_id_hub.clone(),
              incomplete.load_data.inherited_secure_context,
@@ -459,7 +490,7 @@
              incomplete.theme,
              self.this.clone(),
          );
-@@ -3655,6 +3983,8 @@
+@@ -3655,6 +3987,8 @@
              );
          }
 
@@ -468,7 +499,7 @@
          document.set_ready_state(cx, DocumentReadyState::Loading);
 
          self.documents
-@@ -3661,8 +3991,6 @@
+@@ -3661,8 +3995,6 @@
              .borrow_mut()
              .insert(incomplete.pipeline_id, &document);
 
@@ -477,7 +508,7 @@
          // Initialize the browsing context for the window.
          let window_proxy = self.window_proxies.local_window_proxy(
              cx,
-@@ -3673,6 +4001,7 @@
+@@ -3673,6 +4005,7 @@
              incomplete.webview_id,
              incomplete.parent_info,
              incomplete.opener,
@@ -485,7 +516,7 @@
          );
          if window_proxy.parent().is_some() {
              // https://html.spec.whatwg.org/multipage/#navigating-across-documents:delaying-load-events-mode-2
-@@ -3845,11 +4174,11 @@
+@@ -3845,11 +4178,11 @@
          target_snapshot_params: TargetSnapshotParams,
          cx: &mut js::context::JSContext,
      ) {
@@ -500,7 +531,7 @@
              iframe.navigate_or_reload_child_browsing_context(
                  load_data,
                  history_handling,
-@@ -3857,7 +4186,17 @@
+@@ -3857,7 +4190,17 @@
                  target_snapshot_params,
                  cx,
              );
@@ -518,7 +549,7 @@
      }
 
      /// Turn javascript: URL into JS code to eval, according to the steps in
-@@ -4406,10 +4745,88 @@
+@@ -4406,10 +4749,88 @@
          document.event_handler().handle_refresh_cursor();
      }
 
@@ -607,7 +638,7 @@
      fn handle_request_screenshot_readiness(
          &self,
          webview_id: WebViewId,
-@@ -4450,7 +4867,7 @@
+@@ -4450,7 +4871,7 @@
          pinch_zoom_infos: PinchZoomInfos,
      ) {
          let Some(window) = self.documents.borrow().find_window(pipeline_id) else {