--- a/servo/components/style/properties/gecko.mako.rs
+++ b/servo/components/style/properties/gecko.mako.rs
@@ -1317,17 +1317,17 @@ fn static_assert() {
         for (servo, gecko) in v.0.into_iter().zip(self.gecko.m${type.capitalize()}s.iter_mut()) {
             gecko.m${gecko_ffi_name} = servo.seconds() * 1000.;
         }
     }
     #[allow(non_snake_case)]
     pub fn ${type}_${ident}_at(&self, index: usize)
         -> longhands::${type}_${ident}::computed_value::SingleComputedValue {
         use values::specified::Time;
-        Time(self.gecko.mAnimations[index].m${gecko_ffi_name} / 1000.)
+        Time(self.gecko.m${type.capitalize()}s[index].m${gecko_ffi_name} / 1000.)
     }
     ${impl_animation_or_transition_count(type, ident, gecko_ffi_name)}
     ${impl_copy_animation_or_transition_value(type, ident, gecko_ffi_name)}
 </%def>
 
 <%def name="impl_animation_or_transition_timing_function(type)">
     pub fn set_${type}_timing_function(&mut self, v: longhands::${type}_timing_function::computed_value::T) {
         debug_assert!(!v.0.is_empty());