diff --git a/components/style/values/computed/mod.rs b/components/style/values/computed/mod.rs
index da5c84aed39..aaa2677777b 100644
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@@ -465,6 +465,54 @@ trivial_to_computed_value!(String);
 trivial_to_computed_value!(Box<str>);
 trivial_to_computed_value!(crate::OwnedStr);
 
+#[allow(missing_docs)]
+#[derive(
+    Animate,
+    Clone,
+    ComputeSquaredDistance,
+    Copy,
+    Debug,
+    MallocSizeOf,
+    PartialEq,
+    ToAnimatedZero,
+    ToCss,
+    ToResolvedValue,
+)]
+#[repr(C, u8)]
+pub enum AngleOrPercentage {
+    Percentage(Percentage),
+    Angle(Angle),
+}
+
+impl ToComputedValue for specified::AngleOrPercentage {
+    type ComputedValue = AngleOrPercentage;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> AngleOrPercentage {
+        match *self {
+            specified::AngleOrPercentage::Percentage(percentage) => {
+                AngleOrPercentage::Percentage(percentage.to_computed_value(context))
+            },
+            specified::AngleOrPercentage::Angle(angle) => {
+                AngleOrPercentage::Angle(angle.to_computed_value(context))
+            },
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &AngleOrPercentage) -> Self {
+        match *computed {
+            AngleOrPercentage::Percentage(percentage) => {
+                specified::AngleOrPercentage::Percentage(ToComputedValue::from_computed_value(
+                    &percentage,
+                ))
+            },
+            AngleOrPercentage::Angle(angle) => {
+                specified::AngleOrPercentage::Angle(ToComputedValue::from_computed_value(&angle))
+            },
+        }
+    }
+}
+
 /// A `<number>` value.
 pub type Number = CSSFloat;
 
diff --git a/components/style/values/specified/angle.rs b/components/style/values/specified/angle.rs
index 6485bca6f8f..b42d5d5038f 100644
--- a/components/style/values/specified/angle.rs
+++ b/components/style/values/specified/angle.rs
@@ -163,7 +163,8 @@ impl Angle {
 ///   https://github.com/w3c/fxtf-drafts/issues/228
 ///
 /// See also: https://github.com/w3c/csswg-drafts/issues/1162.
-enum AllowUnitlessZeroAngle {
+#[allow(missing_docs)]
+pub enum AllowUnitlessZeroAngle {
     Yes,
     No,
 }
@@ -203,7 +204,7 @@ impl Angle {
         Self::parse_internal(context, input, AllowUnitlessZeroAngle::Yes)
     }
 
-    fn parse_internal<'i, 't>(
+    pub(super) fn parse_internal<'i, 't>(
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
         allow_unitless_zero: AllowUnitlessZeroAngle,
diff --git a/components/style/values/specified/mod.rs b/components/style/values/specified/mod.rs
index 8399456a491..2d8160b17b9 100644
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@@ -31,7 +31,7 @@ use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKin
 pub use self::align::{AlignContent, AlignItems, AlignSelf, ContentDistribution};
 #[cfg(feature = "gecko")]
 pub use self::align::{JustifyContent, JustifyItems, JustifySelf, SelfAlignment};
-pub use self::angle::Angle;
+pub use self::angle::{Angle, AllowUnitlessZeroAngle};
 pub use self::background::{BackgroundRepeat, BackgroundSize};
 pub use self::basic_shape::FillRule;
 pub use self::border::{BorderCornerRadius, BorderImageSlice, BorderImageWidth};
@@ -130,6 +130,47 @@ pub mod transform;
 pub mod ui;
 pub mod url;
 
+/// <angle> | <percentage>
+/// https://drafts.csswg.org/css-values/#typedef-angle-percentage
+#[allow(missing_docs)]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
+pub enum AngleOrPercentage {
+    Percentage(Percentage),
+    Angle(Angle),
+}
+
+impl AngleOrPercentage {
+    fn parse_internal<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+        allow_unitless_zero: AllowUnitlessZeroAngle,
+    ) -> Result<Self, ParseError<'i>> {
+        if let Ok(per) = input.try(|i| Percentage::parse(context, i)) {
+            return Ok(AngleOrPercentage::Percentage(per));
+        }
+
+        Angle::parse_internal(context, input, allow_unitless_zero).map(AngleOrPercentage::Angle)
+    }
+
+    /// Allow unitless angles, used for conic-gradients as specified by the spec.
+    /// https://drafts.csswg.org/css-images-4/#valdef-conic-gradient-angle
+    pub fn parse_with_unitless<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        AngleOrPercentage::parse_internal(context, input, AllowUnitlessZeroAngle::Yes)
+    }
+}
+
+impl Parse for AngleOrPercentage {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        AngleOrPercentage::parse_internal(context, input, AllowUnitlessZeroAngle::No)
+    }
+}
+
 /// Parse a `<number>` value, with a given clamping mode.
 fn parse_number_with_clamping_mode<'i, 't>(
     context: &ParserContext,