diff --git a/layout/style/ServoBindings.toml b/layout/style/ServoBindings.toml
index d9baaa1cd17d..958499c18576 100644
--- a/layout/style/ServoBindings.toml
+++ b/layout/style/ServoBindings.toml
@@ -636,6 +636,7 @@ cbindgen-types = [
     { gecko = "StyleFontStretch", servo = "crate::values::computed::font::FontStretch" },
     { gecko = "StyleFontPalette", servo = "crate::values::computed::font::FontPalette" },
     { gecko = "StyleBoolInteger", servo = "crate::values::computed::BoolInteger" },
+    { gecko = "StyleTime", servo = "crate::values::computed::Time" },
 ]
 
 mapped-generic-types = [
diff --git a/layout/style/nsAnimationManager.cpp b/layout/style/nsAnimationManager.cpp
index 196d4156de03..39f2fff58bff 100644
--- a/layout/style/nsAnimationManager.cpp
+++ b/layout/style/nsAnimationManager.cpp
@@ -248,7 +248,8 @@ static already_AddRefed<CSSAnimation> BuildAnimation(
   }
 
   TimingParams timing = TimingParamsFromCSSParams(
-      aStyle.GetAnimationDuration(animIdx), aStyle.GetAnimationDelay(animIdx),
+      aStyle.GetAnimationDuration(animIdx).ToMilliseconds(),
+      aStyle.GetAnimationDelay(animIdx).ToMilliseconds(),
       aStyle.GetAnimationIterationCount(animIdx),
       aStyle.GetAnimationDirection(animIdx),
       aStyle.GetAnimationFillMode(animIdx));
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
index 6b39e4ee9449..eb6f2205ef0c 100644
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -2167,8 +2167,8 @@ StyleTransition::StyleTransition(const StyleTransition& aCopy) = default;
 void StyleTransition::SetInitialValues() {
   mTimingFunction =
       StyleComputedTimingFunction::Keyword(StyleTimingKeyword::Ease);
-  mDuration = 0.0;
-  mDelay = 0.0;
+  mDuration = {0.0};
+  mDelay = {0.0};
   mProperty = eCSSPropertyExtra_all_properties;
 }
 
@@ -2185,8 +2185,8 @@ StyleAnimation::StyleAnimation(const StyleAnimation& aCopy) = default;
 void StyleAnimation::SetInitialValues() {
   mTimingFunction =
       StyleComputedTimingFunction::Keyword(StyleTimingKeyword::Ease);
-  mDuration = 0.0;
-  mDelay = 0.0;
+  mDuration = {0.0};
+  mDelay = {0.0};
   mName = nsGkAtoms::_empty;
   mDirection = dom::PlaybackDirection::Normal;
   mFillMode = dom::FillMode::None;
diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index 4a0979dea225..dbf113810645 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -1196,8 +1196,7 @@ inline bool StyleTextUnderlinePosition::IsRight() const {
 }
 
 struct StyleTransition {
-  StyleTransition() { /* leaves uninitialized; see also SetInitialValues */
-  }
+  StyleTransition() = default;
   explicit StyleTransition(const StyleTransition& aCopy);
 
   void SetInitialValues();
@@ -1207,8 +1206,8 @@ struct StyleTransition {
   const StyleComputedTimingFunction& GetTimingFunction() const {
     return mTimingFunction;
   }
-  float GetDelay() const { return mDelay; }
-  float GetDuration() const { return mDuration; }
+  const mozilla::StyleTime& GetDelay() const { return mDelay; }
+  const mozilla::StyleTime& GetDuration() const { return mDuration; }
   nsCSSPropertyID GetProperty() const { return mProperty; }
   nsAtom* GetUnknownProperty() const { return mUnknownProperty; }
 
@@ -1219,8 +1218,8 @@ struct StyleTransition {
 
  private:
   StyleComputedTimingFunction mTimingFunction;
-  float mDuration;
-  float mDelay;
+  mozilla::StyleTime mDuration{0.0};
+  mozilla::StyleTime mDelay{0.0};
   nsCSSPropertyID mProperty;
   RefPtr<nsAtom> mUnknownProperty;  // used when mProperty is
                                     // eCSSProperty_UNKNOWN or
@@ -1228,8 +1227,7 @@ struct StyleTransition {
 };
 
 struct StyleAnimation {
-  StyleAnimation() { /* leaves uninitialized; see also SetInitialValues */
-  }
+  StyleAnimation() = default;
   explicit StyleAnimation(const StyleAnimation& aCopy);
 
   void SetInitialValues();
@@ -1239,8 +1237,8 @@ struct StyleAnimation {
   const StyleComputedTimingFunction& GetTimingFunction() const {
     return mTimingFunction;
   }
-  float GetDelay() const { return mDelay; }
-  float GetDuration() const { return mDuration; }
+  const mozilla::StyleTime& GetDelay() const { return mDelay; }
+  const mozilla::StyleTime& GetDuration() const { return mDuration; }
   nsAtom* GetName() const { return mName; }
   dom::PlaybackDirection GetDirection() const { return mDirection; }
   dom::FillMode GetFillMode() const { return mFillMode; }
@@ -1259,8 +1257,8 @@ struct StyleAnimation {
 
  private:
   StyleComputedTimingFunction mTimingFunction;
-  float mDuration;
-  float mDelay;
+  StyleTime mDuration{0.0f};
+  StyleTime mDelay{0.0f};
   RefPtr<nsAtom> mName;  // nsGkAtoms::_empty for 'none'
   dom::PlaybackDirection mDirection;
   dom::FillMode mFillMode;
@@ -1799,10 +1797,10 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleUIReset {
   nsCSSPropertyID GetTransitionProperty(uint32_t aIndex) const {
     return mTransitions[aIndex % mTransitionPropertyCount].GetProperty();
   }
-  float GetTransitionDelay(uint32_t aIndex) const {
+  const mozilla::StyleTime& GetTransitionDelay(uint32_t aIndex) const {
     return mTransitions[aIndex % mTransitionDelayCount].GetDelay();
   }
-  float GetTransitionDuration(uint32_t aIndex) const {
+  const mozilla::StyleTime& GetTransitionDuration(uint32_t aIndex) const {
     return mTransitions[aIndex % mTransitionDurationCount].GetDuration();
   }
   const mozilla::StyleComputedTimingFunction& GetTransitionTimingFunction(
@@ -1810,21 +1808,19 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleUIReset {
     return mTransitions[aIndex % mTransitionTimingFunctionCount]
         .GetTimingFunction();
   }
-  float GetTransitionCombinedDuration(uint32_t aIndex) const {
+  mozilla::StyleTime GetTransitionCombinedDuration(uint32_t aIndex) const {
     // https://drafts.csswg.org/css-transitions/#transition-combined-duration
-    return std::max(
-               mTransitions[aIndex % mTransitionDurationCount].GetDuration(),
-               0.0f) +
-           mTransitions[aIndex % mTransitionDelayCount].GetDelay();
+    return {std::max(GetTransitionDuration(aIndex).seconds, 0.0f) +
+            GetTransitionDelay(aIndex).seconds};
   }
 
   nsAtom* GetAnimationName(uint32_t aIndex) const {
     return mAnimations[aIndex % mAnimationNameCount].GetName();
   }
-  float GetAnimationDelay(uint32_t aIndex) const {
+  const mozilla::StyleTime& GetAnimationDelay(uint32_t aIndex) const {
     return mAnimations[aIndex % mAnimationDelayCount].GetDelay();
   }
-  float GetAnimationDuration(uint32_t aIndex) const {
+  const mozilla::StyleTime& GetAnimationDuration(uint32_t aIndex) const {
     return mAnimations[aIndex % mAnimationDurationCount].GetDuration();
   }
   mozilla::dom::PlaybackDirection GetAnimationDirection(uint32_t aIndex) const {
diff --git a/layout/style/nsTransitionManager.cpp b/layout/style/nsTransitionManager.cpp
index 95f1a5056cbd..4cc7d73e198e 100644
--- a/layout/style/nsTransitionManager.cpp
+++ b/layout/style/nsTransitionManager.cpp
@@ -86,7 +86,7 @@ bool nsTransitionManager::DoUpdateTransitions(
   for (uint32_t i = aStyle.mTransitionPropertyCount; i--;) {
     // We're not going to look at any further transitions, so we can just avoid
     // looking at this if we know it will not start any transitions.
-    if (i == 0 && aStyle.GetTransitionCombinedDuration(i) <= 0.0f) {
+    if (i == 0 && aStyle.GetTransitionCombinedDuration(i).seconds <= 0.0f) {
       continue;
     }
 
@@ -310,10 +310,10 @@ bool nsTransitionManager::ConsiderInitiatingTransition(
     return false;
   }
 
-  float delay = aStyle.GetTransitionDelay(transitionIdx);
+  float delay = aStyle.GetTransitionDelay(transitionIdx).ToMilliseconds();
 
   // The spec says a negative duration is treated as zero.
-  float duration = std::max(aStyle.GetTransitionDuration(transitionIdx), 0.0f);
+  float duration = std::max(aStyle.GetTransitionDuration(transitionIdx).ToMilliseconds(), 0.0f);
 
   // If the combined duration of this transition is 0 or less don't start a
   // transition.
diff --git a/servo/components/style/gecko/wrapper.rs b/servo/components/style/gecko/wrapper.rs
index bf06761d6f00..e09fb9e9af05 100644
--- a/servo/components/style/gecko/wrapper.rs
+++ b/servo/components/style/gecko/wrapper.rs
@@ -858,7 +858,7 @@ impl<'le> GeckoElement<'le> {
     fn needs_transitions_update_per_property(
         &self,
         longhand_id: LonghandId,
-        combined_duration: f32,
+        combined_duration_seconds: f32,
         before_change_style: &ComputedValues,
         after_change_style: &ComputedValues,
         existing_transitions: &FxHashMap<LonghandId, Arc<AnimationValue>>,
@@ -884,7 +884,7 @@ impl<'le> GeckoElement<'le> {
 
         debug_assert_eq!(to.is_some(), from.is_some());
 
-        combined_duration > 0.0f32 &&
+        combined_duration_seconds > 0.0f32 &&
             from != to &&
             from.unwrap()
                 .animate(
@@ -1533,7 +1533,7 @@ impl<'le> TElement for GeckoElement<'le> {
             transitions_to_keep.insert(physical_longhand);
             if self.needs_transitions_update_per_property(
                 physical_longhand,
-                after_change_ui_style.transition_combined_duration_at(transition_property.index),
+                after_change_ui_style.transition_combined_duration_at(transition_property.index).seconds(),
                 before_change_style,
                 after_change_style,
                 &existing_transitions,
diff --git a/servo/components/style/properties/gecko.mako.rs b/servo/components/style/properties/gecko.mako.rs
index c799ebdb03f9..bb134a64ac98 100644
--- a/servo/components/style/properties/gecko.mako.rs
+++ b/servo/components/style/properties/gecko.mako.rs
@@ -39,8 +39,7 @@ use servo_arc::{Arc, RawOffsetArc, UniqueArc};
 use std::mem::{forget, MaybeUninit};
 use std::{cmp, ops, ptr};
 use crate::values::{self, CustomIdent, KeyframesName};
-use crate::values::computed::{Percentage, TransitionProperty};
-use crate::values::computed::BorderStyle;
+use crate::values::computed::{BorderStyle, Percentage, Time, TransitionProperty};
 use crate::values::computed::font::FontSize;
 use crate::values::generics::column::ColumnCount;
 
@@ -1038,14 +1037,13 @@ fn static_assert() {
 
         self.gecko.m${type.capitalize()}${gecko_ffi_name}Count = input_len as u32;
         for (gecko, servo) in self.gecko.m${type.capitalize()}s.iter_mut().take(input_len as usize).zip(v) {
-            gecko.m${gecko_ffi_name} = servo.seconds() * 1000.;
+            gecko.m${gecko_ffi_name} = servo;
         }
     }
     #[allow(non_snake_case)]
     pub fn ${type}_${ident}_at(&self, index: usize)
         -> longhands::${type}_${ident}::computed_value::SingleComputedValue {
-        use crate::values::computed::Time;
-        Time::from_seconds(self.gecko.m${type.capitalize()}s[index].m${gecko_ffi_name} / 1000.)
+        self.gecko.m${type.capitalize()}s[index].m${gecko_ffi_name}
     }
     ${impl_animation_or_transition_count(type, ident, gecko_ffi_name)}
     ${impl_copy_animation_or_transition_value(type, ident, gecko_ffi_name)}
@@ -1772,10 +1770,12 @@ mask-mode mask-repeat mask-clip mask-origin mask-composite mask-position-x mask-
     ${impl_transition_time_value('duration', 'Duration')}
     ${impl_animation_or_transition_timing_function('transition')}
 
-    pub fn transition_combined_duration_at(&self, index: usize) -> f32 {
+    pub fn transition_combined_duration_at(&self, index: usize) -> Time {
         // https://drafts.csswg.org/css-transitions/#transition-combined-duration
-        self.gecko.mTransitions[index % self.gecko.mTransitionDurationCount as usize].mDuration.max(0.0)
-            + self.gecko.mTransitions[index % self.gecko.mTransitionDelayCount as usize].mDelay
+        Time::from_seconds(
+            self.transition_duration_at(index).seconds().max(0.0) +
+            self.transition_delay_at(index).seconds()
+        )
     }
 
     pub fn set_transition_property<I>(&mut self, v: I)
@@ -1818,7 +1818,7 @@ mask-mode mask-repeat mask-clip mask-origin mask-composite mask-position-x mask-
         use crate::gecko_bindings::structs::nsCSSPropertyID::eCSSPropertyExtra_all_properties;
         if self.gecko.mTransitionPropertyCount == 1 &&
             self.gecko.mTransitions[0].mProperty == eCSSPropertyExtra_all_properties &&
-            self.transition_combined_duration_at(0) <= 0.0f32 {
+            self.transition_combined_duration_at(0).seconds() <= 0.0f32 {
             return false;
         }
 
diff --git a/servo/components/style/values/computed/time.rs b/servo/components/style/values/computed/time.rs
index 5681f6fab5e6..1f0a6df018ba 100644
--- a/servo/components/style/values/computed/time.rs
+++ b/servo/components/style/values/computed/time.rs
@@ -11,6 +11,7 @@ use style_traits::{CssWriter, ToCss};
 /// A computed `<time>` value.
 #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd, ToResolvedValue)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
+#[repr(C)]
 pub struct Time {
     seconds: CSSFloat,
 }
@@ -18,7 +19,7 @@ pub struct Time {
 impl Time {
     /// Creates a time value from a seconds amount.
     pub fn from_seconds(seconds: CSSFloat) -> Self {
-        Time { seconds: seconds }
+        Time { seconds }
     }
 
     /// Returns `0s`.
diff --git a/servo/ports/geckolib/cbindgen.toml b/servo/ports/geckolib/cbindgen.toml
index c445d2800fd4..fb3249df0215 100644
--- a/servo/ports/geckolib/cbindgen.toml
+++ b/servo/ports/geckolib/cbindgen.toml
@@ -135,6 +135,7 @@ include = [
   "NonNegativeLengthOrAuto",
   "TextDecorationSkipInk",
   "TextDecorationLength",
+  "Time",
   "Rect",
   "IntersectionObserverRootMargin",
   "Size",
@@ -950,6 +951,11 @@ renaming_overrides_prefixing = true
   StyleScrollTimelineName(): _0(RefPtr<nsAtom>(nsGkAtoms::_empty).forget()) {}
 """
 
+"Time" = """
+ float ToSeconds() const { return seconds; }
+ float ToMilliseconds() const { return seconds * 1000.0f; }
+"""
+
 "FontFaceSourceTechFlags" = """
   inline static StyleFontFaceSourceTechFlags Empty() {
     return StyleFontFaceSourceTechFlags{0};