diff --git a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
index 85346ecf08..9fbde739a3 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -8770,6 +8770,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override { VERIFY_NOT_REACHED(); }
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override { VERIFY_NOT_REACHED(); }
+    virtual Optional<CSSNumericType> determine_type(Web::CSS::PropertyID) const override { VERIFY_NOT_REACHED(); }
     virtual bool contains_percentage() const override { VERIFY_NOT_REACHED(); }
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override { VERIFY_NOT_REACHED(); }
 
diff --git a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp
index a896230e63..e97129bf85 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.cpp
@@ -9,6 +9,7 @@
 
 #include "CalculatedStyleValue.h"
 #include <LibWeb/CSS/Percentage.h>
+#include <LibWeb/CSS/PropertyID.h>
 
 namespace Web::CSS {
 
@@ -43,6 +44,27 @@ static double resolve_value(CalculatedStyleValue::CalculationResult::Value value
         [](Time const& time) { return time.to_seconds(); });
 };
 
+static Optional<CSSNumericType> add_the_types(Vector<NonnullOwnPtr<CalculationNode>> const& nodes, PropertyID property_id)
+{
+    Optional<CSSNumericType> left_type;
+    for (auto const& value : nodes) {
+        auto right_type = value->determine_type(property_id);
+        if (!right_type.has_value())
+            return {};
+
+        if (left_type.has_value()) {
+            left_type = left_type->added_to(right_type.value());
+        } else {
+            left_type = right_type;
+        }
+
+        if (!left_type.has_value())
+            return {};
+    }
+
+    return left_type;
+}
+
 static CalculatedStyleValue::CalculationResult to_resolved_type(CalculatedStyleValue::ResolvedType type, double value)
 {
     switch (type) {
@@ -101,6 +123,59 @@ Optional<CalculatedStyleValue::ResolvedType> NumericCalculationNode::resolved_ty
         [](Time const&) { return CalculatedStyleValue::ResolvedType::Time; });
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> NumericCalculationNode::determine_type(PropertyID property_id) const
+{
+    // Anything else is a terminal value, whose type is determined based on its CSS type:
+    return m_value.visit(
+        [](Number const&) {
+            // -> <number>
+            // -> <integer>
+            //    the type is «[ ]» (empty map)
+            return CSSNumericType {};
+        },
+        [](Length const&) {
+            // -> <length>
+            //    the type is «[ "length" → 1 ]»
+            return CSSNumericType { CSSNumericType::BaseType::Length, 1 };
+        },
+        [](Angle const&) {
+            // -> <angle>
+            //    the type is «[ "angle" → 1 ]»
+            return CSSNumericType { CSSNumericType::BaseType::Angle, 1 };
+        },
+        [](Time const&) {
+            // -> <time>
+            //    the type is «[ "time" → 1 ]»
+            return CSSNumericType { CSSNumericType::BaseType::Time, 1 };
+        },
+        [](Frequency const&) {
+            // -> <frequency>
+            //    the type is «[ "frequency" → 1 ]»
+            return CSSNumericType { CSSNumericType::BaseType::Frequency, 1 };
+        },
+        // FIXME: <resolution>
+        // FIXME: <flex>
+        // NOTE: <calc-constant> is a separate node type. (FIXME: Should it be?)
+        [property_id](Percentage const&) {
+            // -> <percentage>
+            //    If, in the context in which the math function containing this calculation is placed,
+            //    <percentage>s are resolved relative to another type of value (such as in width,
+            //    where <percentage> is resolved against a <length>), and that other type is not <number>,
+            //    the type is determined as the other type.
+            auto percentage_resolved_type = property_resolves_percentages_relative_to(property_id);
+            if (percentage_resolved_type.has_value() && percentage_resolved_type != ValueType::Number && percentage_resolved_type != ValueType::Percentage) {
+                auto base_type = CSSNumericType::base_type_from_value_type(*percentage_resolved_type);
+                VERIFY(base_type.has_value());
+                return CSSNumericType { base_type.value(), 1 };
+            }
+
+            //    Otherwise, the type is «[ "percent" → 1 ]».
+            return CSSNumericType { CSSNumericType::BaseType::Percent, 1 };
+        });
+    // In all cases, the associated percent hint is null.
+}
+
 bool NumericCalculationNode::contains_percentage() const
 {
     return m_value.has<Percentage>();
@@ -185,6 +260,15 @@ Optional<CalculatedStyleValue::ResolvedType> SumCalculationNode::resolved_type()
     return type;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> SumCalculationNode::determine_type(PropertyID property_id) const
+{
+    // At a + or - sub-expression, attempt to add the types of the left and right arguments.
+    // If this returns failure, the entire calculation’s type is failure.
+    // Otherwise, the sub-expression’s type is the returned type.
+    return add_the_types(m_values, property_id);
+}
+
 bool SumCalculationNode::contains_percentage() const
 {
     for (auto const& value : m_values) {
@@ -287,6 +371,30 @@ Optional<CalculatedStyleValue::ResolvedType> ProductCalculationNode::resolved_ty
     return type;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> ProductCalculationNode::determine_type(PropertyID property_id) const
+{
+    // At a * sub-expression, multiply the types of the left and right arguments.
+    // The sub-expression’s type is the returned result.
+    Optional<CSSNumericType> left_type;
+    for (auto const& value : m_values) {
+        auto right_type = value->determine_type(property_id);
+        if (!right_type.has_value())
+            return {};
+
+        if (left_type.has_value()) {
+            left_type = left_type->multiplied_by(right_type.value());
+        } else {
+            left_type = right_type;
+        }
+
+        if (!left_type.has_value())
+            return {};
+    }
+
+    return left_type;
+}
+
 bool ProductCalculationNode::contains_percentage() const
 {
     for (auto const& value : m_values) {
@@ -353,6 +461,13 @@ Optional<CalculatedStyleValue::ResolvedType> NegateCalculationNode::resolved_typ
     return m_value->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> NegateCalculationNode::determine_type(PropertyID property_id) const
+{
+    // NOTE: `- foo` doesn't change the type
+    return m_value->determine_type(property_id);
+}
+
 bool NegateCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -405,6 +520,17 @@ Optional<CalculatedStyleValue::ResolvedType> InvertCalculationNode::resolved_typ
     return type;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> InvertCalculationNode::determine_type(PropertyID property_id) const
+{
+    // At a / sub-expression, let left type be the result of finding the types of its left argument,
+    // and right type be the result of finding the types of its right argument and then inverting it.
+    // The sub-expression’s type is the result of multiplying the left type and right type.
+    // NOTE: An InvertCalculationNode only represents the right argument here, and the multiplication
+    //       is handled in the parent ProductCalculationNode.
+    return m_value->determine_type(property_id).map([](auto& it) { return it.inverted(); });
+}
+
 bool InvertCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -463,6 +589,13 @@ Optional<CalculatedStyleValue::ResolvedType> MinCalculationNode::resolved_type()
     return m_values[0]->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> MinCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    return add_the_types(m_values, property_id);
+}
+
 bool MinCalculationNode::contains_percentage() const
 {
     for (auto const& value : m_values) {
@@ -541,6 +674,13 @@ Optional<CalculatedStyleValue::ResolvedType> MaxCalculationNode::resolved_type()
     return m_values[0]->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> MaxCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    return add_the_types(m_values, property_id);
+}
+
 bool MaxCalculationNode::contains_percentage() const
 {
     for (auto const& value : m_values) {
@@ -621,6 +761,23 @@ Optional<CalculatedStyleValue::ResolvedType> ClampCalculationNode::resolved_type
     return m_min_value->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> ClampCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    auto min_type = m_min_value->determine_type(property_id);
+    auto center_type = m_center_value->determine_type(property_id);
+    auto max_type = m_max_value->determine_type(property_id);
+
+    if (!min_type.has_value() || !center_type.has_value() || !max_type.has_value())
+        return {};
+
+    auto result = min_type->added_to(*center_type);
+    if (!result.has_value())
+        return {};
+    return result->added_to(*max_type);
+}
+
 bool ClampCalculationNode::contains_percentage() const
 {
     return m_min_value->contains_percentage() || m_center_value->contains_percentage() || m_max_value->contains_percentage();
@@ -696,6 +853,13 @@ Optional<CalculatedStyleValue::ResolvedType> AbsCalculationNode::resolved_type()
     return m_value->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> AbsCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The type of its contained calculation.
+    return m_value->determine_type(property_id);
+}
+
 bool AbsCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -753,6 +917,13 @@ Optional<CalculatedStyleValue::ResolvedType> SignCalculationNode::resolved_type(
     return CalculatedStyleValue::ResolvedType::Integer;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> SignCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 bool SignCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -820,6 +991,15 @@ Optional<CalculatedStyleValue::ResolvedType> ConstantCalculationNode::resolved_t
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> ConstantCalculationNode::determine_type(PropertyID) const
+{
+    // Anything else is a terminal value, whose type is determined based on its CSS type:
+    // -> <calc-constant>
+    //    the type is «[ ]» (empty map)
+    return CSSNumericType {};
+}
+
 CalculatedStyleValue::CalculationResult ConstantCalculationNode::resolve([[maybe_unused]] Optional<Length::ResolutionContext const&> context, [[maybe_unused]] CalculatedStyleValue::PercentageBasis const& percentage_basis) const
 {
     switch (m_constant) {
@@ -877,6 +1057,13 @@ Optional<CalculatedStyleValue::ResolvedType> SinCalculationNode::resolved_type()
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> SinCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 bool SinCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -931,6 +1118,13 @@ Optional<CalculatedStyleValue::ResolvedType> CosCalculationNode::resolved_type()
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> CosCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 bool CosCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -985,6 +1179,13 @@ Optional<CalculatedStyleValue::ResolvedType> TanCalculationNode::resolved_type()
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> TanCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 bool TanCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -1039,6 +1240,13 @@ Optional<CalculatedStyleValue::ResolvedType> AsinCalculationNode::resolved_type(
     return CalculatedStyleValue::ResolvedType::Angle;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> AsinCalculationNode::determine_type(PropertyID) const
+{
+    // NOTE: Spec is currently wrong: https://github.com/w3c/csswg-drafts/issues/9034
+    return CSSNumericType { CSSNumericType::BaseType::Angle, 1 };
+}
+
 bool AsinCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -1093,6 +1301,13 @@ Optional<CalculatedStyleValue::ResolvedType> AcosCalculationNode::resolved_type(
     return CalculatedStyleValue::ResolvedType::Angle;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> AcosCalculationNode::determine_type(PropertyID) const
+{
+    // NOTE: Spec is currently wrong: https://github.com/w3c/csswg-drafts/issues/9034
+    return CSSNumericType { CSSNumericType::BaseType::Angle, 1 };
+}
+
 bool AcosCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -1147,6 +1362,13 @@ Optional<CalculatedStyleValue::ResolvedType> AtanCalculationNode::resolved_type(
     return CalculatedStyleValue::ResolvedType::Angle;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> AtanCalculationNode::determine_type(PropertyID) const
+{
+    // NOTE: Spec is currently wrong: https://github.com/w3c/csswg-drafts/issues/9034
+    return CSSNumericType { CSSNumericType::BaseType::Angle, 1 };
+}
+
 bool AtanCalculationNode::contains_percentage() const
 {
     return m_value->contains_percentage();
@@ -1204,6 +1426,13 @@ Optional<CalculatedStyleValue::ResolvedType> Atan2CalculationNode::resolved_type
     return CalculatedStyleValue::ResolvedType::Angle;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> Atan2CalculationNode::determine_type(PropertyID) const
+{
+    // NOTE: Spec is currently wrong: https://github.com/w3c/csswg-drafts/issues/9034
+    return CSSNumericType { CSSNumericType::BaseType::Angle, 1 };
+}
+
 bool Atan2CalculationNode::contains_percentage() const
 {
     return m_y->contains_percentage() || m_x->contains_percentage();
@@ -1267,6 +1496,13 @@ Optional<CalculatedStyleValue::ResolvedType> PowCalculationNode::resolved_type()
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> PowCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 CalculatedStyleValue::CalculationResult PowCalculationNode::resolve(Optional<Length::ResolutionContext const&> context, CalculatedStyleValue::PercentageBasis const& percentage_basis) const
 {
     auto node_a = m_x->resolve(context, percentage_basis);
@@ -1322,6 +1558,13 @@ Optional<CalculatedStyleValue::ResolvedType> SqrtCalculationNode::resolved_type(
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> SqrtCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 CalculatedStyleValue::CalculationResult SqrtCalculationNode::resolve(Optional<Length::ResolutionContext const&> context, CalculatedStyleValue::PercentageBasis const& percentage_basis) const
 {
     auto node_a = m_value->resolve(context, percentage_basis);
@@ -1376,6 +1619,13 @@ Optional<CalculatedStyleValue::ResolvedType> HypotCalculationNode::resolved_type
     return m_values[0]->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> HypotCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    return add_the_types(m_values, property_id);
+}
+
 bool HypotCalculationNode::contains_percentage() const
 {
     for (auto const& value : m_values) {
@@ -1450,6 +1700,13 @@ Optional<CalculatedStyleValue::ResolvedType> LogCalculationNode::resolved_type()
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> LogCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 CalculatedStyleValue::CalculationResult LogCalculationNode::resolve(Optional<Length::ResolutionContext const&> context, CalculatedStyleValue::PercentageBasis const& percentage_basis) const
 {
     auto node_a = m_x->resolve(context, percentage_basis);
@@ -1505,6 +1762,13 @@ Optional<CalculatedStyleValue::ResolvedType> ExpCalculationNode::resolved_type()
     return CalculatedStyleValue::ResolvedType::Number;
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> ExpCalculationNode::determine_type(PropertyID) const
+{
+    // «[ ]» (empty map).
+    return CSSNumericType {};
+}
+
 CalculatedStyleValue::CalculationResult ExpCalculationNode::resolve(Optional<Length::ResolutionContext const&> context, CalculatedStyleValue::PercentageBasis const& percentage_basis) const
 {
     auto node_a = m_value->resolve(context, percentage_basis);
@@ -1574,6 +1838,19 @@ Optional<CalculatedStyleValue::ResolvedType> RoundCalculationNode::resolved_type
     return m_x->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> RoundCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    auto x_type = m_x->determine_type(property_id);
+    auto y_type = m_y->determine_type(property_id);
+
+    if (!x_type.has_value() || !y_type.has_value())
+        return {};
+
+    return x_type->added_to(*y_type);
+}
+
 bool RoundCalculationNode::contains_percentage() const
 {
     return m_x->contains_percentage() || m_y->contains_percentage();
@@ -1662,6 +1939,19 @@ Optional<CalculatedStyleValue::ResolvedType> ModCalculationNode::resolved_type()
     return m_x->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> ModCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    auto x_type = m_x->determine_type(property_id);
+    auto y_type = m_y->determine_type(property_id);
+
+    if (!x_type.has_value() || !y_type.has_value())
+        return {};
+
+    return x_type->added_to(*y_type);
+}
+
 bool ModCalculationNode::contains_percentage() const
 {
     return m_x->contains_percentage() || m_y->contains_percentage();
@@ -1727,6 +2017,19 @@ Optional<CalculatedStyleValue::ResolvedType> RemCalculationNode::resolved_type()
     return m_x->resolved_type();
 }
 
+// https://www.w3.org/TR/css-values-4/#determine-the-type-of-a-calculation
+Optional<CSSNumericType> RemCalculationNode::determine_type(PropertyID property_id) const
+{
+    // The result of adding the types of its comma-separated calculations.
+    auto x_type = m_x->determine_type(property_id);
+    auto y_type = m_y->determine_type(property_id);
+
+    if (!x_type.has_value() || !y_type.has_value())
+        return {};
+
+    return x_type->added_to(*y_type);
+}
+
 bool RemCalculationNode::contains_percentage() const
 {
     return m_x->contains_percentage() || m_y->contains_percentage();
diff --git a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h
index a47be2e1dc..e715a96d37 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h
+++ b/Userland/Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h
@@ -10,6 +10,7 @@
 #pragma once
 
 #include <LibWeb/CSS/Angle.h>
+#include <LibWeb/CSS/CSSNumericType.h>
 #include <LibWeb/CSS/Frequency.h>
 #include <LibWeb/CSS/Length.h>
 #include <LibWeb/CSS/Percentage.h>
@@ -237,6 +238,7 @@ public:
 
     virtual ErrorOr<String> to_string() const = 0;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const = 0;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const = 0;
     virtual bool contains_percentage() const = 0;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const = 0;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) { return {}; }
@@ -257,6 +259,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
 
@@ -274,6 +277,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -292,6 +296,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -310,6 +315,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -328,6 +334,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -346,6 +353,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -364,6 +372,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -382,6 +391,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -402,6 +412,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -420,6 +431,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -438,6 +450,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override { return false; };
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&> context, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -456,6 +469,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -474,6 +488,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -492,6 +507,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -510,6 +526,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -528,6 +545,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -546,6 +564,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -564,6 +583,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -583,6 +603,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override { return false; };
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -602,6 +623,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override { return false; };
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -620,6 +642,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -638,6 +661,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override { return false; };
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -657,6 +681,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override { return false; };
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -675,6 +700,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -695,6 +721,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;
@@ -714,6 +741,7 @@ public:
 
     virtual ErrorOr<String> to_string() const override;
     virtual Optional<CalculatedStyleValue::ResolvedType> resolved_type() const override;
+    virtual Optional<CSSNumericType> determine_type(PropertyID) const override;
     virtual bool contains_percentage() const override;
     virtual CalculatedStyleValue::CalculationResult resolve(Optional<Length::ResolutionContext const&>, CalculatedStyleValue::PercentageBasis const&) const override;
     virtual ErrorOr<void> for_each_child_node(Function<ErrorOr<void>(NonnullOwnPtr<CalculationNode>&)> const&) override;