diff --git a/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.cpp b/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.cpp
index fd39275a2b0..b89bd5ff9a2 100644
--- a/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.cpp
+++ b/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.cpp
@@ -109,4 +109,41 @@ Optional<double> CSSColorValue::resolve_alpha(CSSStyleValue const& style_value)
     return {};
 }
 
+void CSSColorValue::serialize_color_component(StringBuilder& builder, SerializationMode mode, CSSStyleValue const& component, float one_hundred_percent_value, Optional<double> clamp_min, Optional<double> clamp_max) const
+{
+    if (component.to_keyword() == Keyword::None) {
+        builder.append("none"sv);
+        return;
+    }
+    if (component.is_calculated() && mode == SerializationMode::Normal) {
+        builder.append(component.to_string(mode));
+        return;
+    }
+    auto resolved_value = resolve_with_reference_value(component, one_hundred_percent_value).value_or(0);
+    if (clamp_min.has_value() && resolved_value < *clamp_min)
+        resolved_value = *clamp_min;
+    if (clamp_max.has_value() && resolved_value > *clamp_max)
+        resolved_value = *clamp_max;
+
+    // FIXME: Find a better way to format a decimal with trimmed trailing zeroes
+    auto resolved_string = MUST(String::formatted("{:.2}", resolved_value));
+    if (resolved_string.contains('.'))
+        resolved_string = MUST(resolved_string.trim("0"sv, TrimMode::Right));
+    builder.append(resolved_string);
+}
+
+void CSSColorValue::serialize_alpha_component(StringBuilder& builder, SerializationMode mode, CSSStyleValue const& component) const
+{
+    if (component.to_keyword() == Keyword::None) {
+        builder.append("none"sv);
+        return;
+    }
+    if (component.is_calculated() && mode == SerializationMode::Normal) {
+        builder.append(component.to_string(mode));
+        return;
+    }
+    auto resolved_value = resolve_alpha(component).value_or(0);
+    builder.appendff("{}", resolved_value);
+}
+
 }
diff --git a/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.h b/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.h
index 00c6e1b2d88..bb5107d2d1b 100644
--- a/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.h
+++ b/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.h
@@ -61,6 +61,9 @@ protected:
     static Optional<double> resolve_with_reference_value(CSSStyleValue const&, float one_hundred_percent_value);
     static Optional<double> resolve_alpha(CSSStyleValue const&);
 
+    void serialize_color_component(StringBuilder& builder, SerializationMode mode, CSSStyleValue const& component, float one_hundred_percent_value, Optional<double> clamp_min = {}, Optional<double> clamp_max = {}) const;
+    void serialize_alpha_component(StringBuilder& builder, SerializationMode mode, CSSStyleValue const& component) const;
+
     ColorType m_color_type;
     ColorSyntax m_color_syntax;
 };
diff --git a/Libraries/LibWeb/CSS/StyleValues/CSSLabLike.cpp b/Libraries/LibWeb/CSS/StyleValues/CSSLabLike.cpp
index 9c55ed098ce..c9848d67dab 100644
--- a/Libraries/LibWeb/CSS/StyleValues/CSSLabLike.cpp
+++ b/Libraries/LibWeb/CSS/StyleValues/CSSLabLike.cpp
@@ -1,11 +1,13 @@
 /*
  * Copyright (c) 2024, Sam Atkins <sam@ladybird.org>
+ * Copyright (c) 2025, Tim Ledbetter <tim.ledbetter@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include "CSSLabLike.h"
 #include <AK/TypeCasts.h>
+#include <LibWeb/CSS/CSSStyleValue.h>
 #include <LibWeb/CSS/Serialize.h>
 #include <LibWeb/CSS/StyleValues/CalculatedStyleValue.h>
 #include <LibWeb/CSS/StyleValues/NumberStyleValue.h>
@@ -35,10 +37,23 @@ Color CSSOKLab::to_color(Optional<Layout::NodeWithStyle const&>) const
 }
 
 // https://www.w3.org/TR/css-color-4/#serializing-oklab-oklch
-String CSSOKLab::to_string(SerializationMode) const
+String CSSOKLab::to_string(SerializationMode mode) const
 {
-    // FIXME: Do this properly, taking unresolved calculated values into account.
-    return serialize_a_srgb_value(to_color({}));
+    StringBuilder builder;
+    builder.append("oklab("sv);
+    serialize_color_component(builder, mode, m_properties.l, 1.0f, 0, 1);
+    builder.append(' ');
+    serialize_color_component(builder, mode, m_properties.a, 0.4f);
+    builder.append(' ');
+    serialize_color_component(builder, mode, m_properties.b, 0.4f);
+    if ((!m_properties.alpha->is_number() || m_properties.alpha->as_number().number() < 1)
+        && (!m_properties.alpha->is_percentage() || m_properties.alpha->as_percentage().percentage().as_fraction() < 1)) {
+        builder.append(" / "sv);
+        serialize_alpha_component(builder, mode, m_properties.alpha);
+    }
+
+    builder.append(')');
+    return MUST(builder.to_string());
 }
 
 Color CSSLab::to_color(Optional<Layout::NodeWithStyle const&>) const
@@ -52,10 +67,23 @@ Color CSSLab::to_color(Optional<Layout::NodeWithStyle const&>) const
 }
 
 // https://www.w3.org/TR/css-color-4/#serializing-lab-lch
-String CSSLab::to_string(SerializationMode) const
+String CSSLab::to_string(SerializationMode mode) const
 {
-    // FIXME: Do this properly, taking unresolved calculated values into account.
-    return serialize_a_srgb_value(to_color({}));
+    StringBuilder builder;
+    builder.append("lab("sv);
+    serialize_color_component(builder, mode, m_properties.l, 100, 0, 100);
+    builder.append(' ');
+    serialize_color_component(builder, mode, m_properties.a, 125);
+    builder.append(' ');
+    serialize_color_component(builder, mode, m_properties.b, 125);
+    if ((!m_properties.alpha->is_number() || m_properties.alpha->as_number().number() < 1)
+        && (!m_properties.alpha->is_percentage() || m_properties.alpha->as_percentage().percentage().as_fraction() < 1)) {
+        builder.append(" / "sv);
+        serialize_alpha_component(builder, mode, m_properties.alpha);
+    }
+
+    builder.append(')');
+    return MUST(builder.to_string());
 }
 
 }
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-color/parsing/color-valid-lab.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-color/parsing/color-valid-lab.txt
new file mode 100644
index 00000000000..de59a756bbf
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-color/parsing/color-valid-lab.txt
@@ -0,0 +1,156 @@
+Harness status: OK
+
+Found 150 tests
+
+70 Pass
+80 Fail
+Pass	e.style['color'] = "lab(0 0 0)" should set the property value
+Pass	e.style['color'] = "lab(0 0 0 / 1)" should set the property value
+Pass	e.style['color'] = "lab(0 0 0 / 0.5)" should set the property value
+Pass	e.style['color'] = "lab(20 0 10/0.5)" should set the property value
+Pass	e.style['color'] = "lab(20 0 10/50%)" should set the property value
+Pass	e.style['color'] = "lab(400 0 10/50%)" should set the property value
+Pass	e.style['color'] = "lab(50 -160 160)" should set the property value
+Pass	e.style['color'] = "lab(50 -200 200)" should set the property value
+Pass	e.style['color'] = "lab(0 0 0 / -10%)" should set the property value
+Pass	e.style['color'] = "lab(0 0 0 / 110%)" should set the property value
+Pass	e.style['color'] = "lab(0 0 0 / 300%)" should set the property value
+Pass	e.style['color'] = "lab(-40 0 0)" should set the property value
+Pass	e.style['color'] = "lab(50 -20 0)" should set the property value
+Pass	e.style['color'] = "lab(50 0 -20)" should set the property value
+Pass	e.style['color'] = "lab(50% 50% -20%)" should set the property value
+Pass	e.style['color'] = "lab(50 -20% -20%)" should set the property value
+Pass	e.style['color'] = "lab(calc(50 * 3) calc(0.5 - 1) calc(1.5) / calc(-0.5 + 1))" should set the property value
+Pass	e.style['color'] = "lab(calc(-50 * 3) calc(0.5 + 1) calc(-1.5) / calc(-0.5 * 2))" should set the property value
+Pass	e.style['color'] = "lab(calc(50%) 50% 0.5)" should set the property value
+Pass	e.style['color'] = "lab(200 calc(50%) 0.5)" should set the property value
+Pass	e.style['color'] = "lab(-200 calc(50%) 0.5)" should set the property value
+Pass	e.style['color'] = "lab(none 20 calc(0.5))" should set the property value
+Pass	e.style['color'] = "lab(none none none / none)" should set the property value
+Pass	e.style['color'] = "lab(none none none)" should set the property value
+Pass	e.style['color'] = "lab(20 none none / none)" should set the property value
+Pass	e.style['color'] = "lab(none none none / 0.5)" should set the property value
+Pass	e.style['color'] = "lab(0 0 0 / none)" should set the property value
+Pass	e.style['color'] = "lab(calc(infinity) 0 0)" should set the property value
+Pass	e.style['color'] = "lab(50 calc(infinity) 0)" should set the property value
+Pass	e.style['color'] = "lab(50 calc(-infinity) 0)" should set the property value
+Pass	e.style['color'] = "lab(calc(NaN) 0 0)" should set the property value
+Pass	e.style['color'] = "lab(calc(0 / 0) 0 0)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0 / 1)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0 / 0.5)" should set the property value
+Pass	e.style['color'] = "oklab(0.2 0 0.1/0.5)" should set the property value
+Pass	e.style['color'] = "oklab(0.2 0 0.1/50%)" should set the property value
+Pass	e.style['color'] = "oklab(4 0 0.1/50%)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 -1.6 1.6)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 -2 2)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0 / -10%)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0 / 110%)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0 / 300%)" should set the property value
+Pass	e.style['color'] = "oklab(-0.4 0 0)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 -2 0)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 0 -2)" should set the property value
+Pass	e.style['color'] = "oklab(50% 50% -20%)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 -20% -20%)" should set the property value
+Pass	e.style['color'] = "oklab(calc(0.5 * 3) calc(0.5 - 1) calc(1.5) / calc(-0.5 + 1))" should set the property value
+Pass	e.style['color'] = "oklab(calc(-0.5 * 3) calc(0.5 + 1) calc(-1.5) / calc(-0.5 * 2))" should set the property value
+Pass	e.style['color'] = "oklab(calc(50%) 50% 0.5)" should set the property value
+Pass	e.style['color'] = "oklab(200 calc(50%) 0.5)" should set the property value
+Pass	e.style['color'] = "oklab(-200 calc(50%) 0.5)" should set the property value
+Pass	e.style['color'] = "oklab(none 0.2 calc(0.5))" should set the property value
+Pass	e.style['color'] = "oklab(none none none / none)" should set the property value
+Pass	e.style['color'] = "oklab(none none none)" should set the property value
+Pass	e.style['color'] = "oklab(0.2 none none / none)" should set the property value
+Pass	e.style['color'] = "oklab(none none none / 0.5)" should set the property value
+Pass	e.style['color'] = "oklab(0 0 0 / none)" should set the property value
+Pass	e.style['color'] = "lab(20% -50% 90%/0.5)" should set the property value
+Pass	e.style['color'] = "oklab(20% 70% -80%/0.5)" should set the property value
+Pass	e.style['color'] = "oklab(calc(infinity) 0 0)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 calc(infinity) 0)" should set the property value
+Pass	e.style['color'] = "oklab(0.5 calc(-infinity) 0)" should set the property value
+Pass	e.style['color'] = "oklab(calc(NaN) 0 0)" should set the property value
+Pass	e.style['color'] = "oklab(calc(0 / 0) 0 0)" should set the property value
+Fail	e.style['color'] = "lch(0 0 0deg)" should set the property value
+Fail	e.style['color'] = "lch(0 0 0deg / 1)" should set the property value
+Fail	e.style['color'] = "lch(0 0 0deg / 0.5)" should set the property value
+Fail	e.style['color'] = "lch(100 230 0deg / 0.5)" should set the property value
+Fail	e.style['color'] = "lch(20 50 20deg/0.5)" should set the property value
+Fail	e.style['color'] = "lch(20 50 20deg/50%)" should set the property value
+Fail	e.style['color'] = "lch(10 20 20deg / -10%)" should set the property value
+Fail	e.style['color'] = "lch(10 20 20deg / 110%)" should set the property value
+Fail	e.style['color'] = "lch(10 20 1.28rad)" should set the property value
+Fail	e.style['color'] = "lch(10 20 380deg)" should set the property value
+Fail	e.style['color'] = "lch(10 20 -340deg)" should set the property value
+Fail	e.style['color'] = "lch(10 20 740deg)" should set the property value
+Fail	e.style['color'] = "lch(10 20 -700deg)" should set the property value
+Fail	e.style['color'] = "lch(-40 0 0)" should set the property value
+Fail	e.style['color'] = "lch(20 -20 0)" should set the property value
+Fail	e.style['color'] = "lch(0 0 0 / 0.5)" should set the property value
+Fail	e.style['color'] = "lch(10 20 20 / 110%)" should set the property value
+Fail	e.style['color'] = "lch(10 20 -700)" should set the property value
+Fail	e.style['color'] = "lch(50% 50% 20)" should set the property value
+Fail	e.style['color'] = "lch(0.5 -20% -20)" should set the property value
+Fail	e.style['color'] = "lch(calc(50 * 3) calc(0.5 - 1) calc(20deg * 2) / calc(-0.5 + 1))" should set the property value
+Fail	e.style['color'] = "lch(calc(-50 * 3) calc(0.5 + 1) calc(-20deg * 2) / calc(-0.5 * 2))" should set the property value
+Fail	e.style['color'] = "lch(calc(50%) 50% 0.5)" should set the property value
+Fail	e.style['color'] = "lch(200 calc(50%) 0.5)" should set the property value
+Fail	e.style['color'] = "lch(-200 calc(50%) 0.5)" should set the property value
+Fail	e.style['color'] = "lch(calc(50%) -100 0.5)" should set the property value
+Fail	e.style['color'] = "lch(none 20 calc(0.5))" should set the property value
+Fail	e.style['color'] = "lch(none none none / none)" should set the property value
+Fail	e.style['color'] = "lch(none none none)" should set the property value
+Fail	e.style['color'] = "lch(20 none none / none)" should set the property value
+Fail	e.style['color'] = "lch(none none none / 0.5)" should set the property value
+Fail	e.style['color'] = "lch(0 0 0 / none)" should set the property value
+Fail	e.style['color'] = "lch(calc(infinity) 0 0)" should set the property value
+Fail	e.style['color'] = "lch(50 calc(infinity) 0)" should set the property value
+Fail	e.style['color'] = "lch(50 calc(-infinity) 0)" should set the property value
+Fail	e.style['color'] = "lch(calc(NaN) 0 0)" should set the property value
+Fail	e.style['color'] = "lch(calc(0 / 0) 0 0)" should set the property value
+Fail	e.style['color'] = "oklch(0 0 0deg)" should set the property value
+Fail	e.style['color'] = "oklch(0 0 0deg / 1)" should set the property value
+Fail	e.style['color'] = "oklch(0 0 0deg / 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(1 2.3 0deg / 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(0.2 0.5 20deg/0.5)" should set the property value
+Fail	e.style['color'] = "oklch(0.2 0.5 20deg/50%)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 20deg / -10%)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 20deg / 110%)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 1.28rad)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 380deg)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 -340deg)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 740deg)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 -700deg)" should set the property value
+Fail	e.style['color'] = "oklch(-4 0 0)" should set the property value
+Fail	e.style['color'] = "oklch(0.2 -0.2 0)" should set the property value
+Fail	e.style['color'] = "oklch(0 0 0 / 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 20 / 110%)" should set the property value
+Fail	e.style['color'] = "oklch(0.1 0.2 -700)" should set the property value
+Fail	e.style['color'] = "oklch(50% 50% 20)" should set the property value
+Fail	e.style['color'] = "oklch(0.5 -20% -20)" should set the property value
+Fail	e.style['color'] = "oklch(calc(0.5 * 3) calc(0.5 - 1) calc(20deg * 2) / calc(-0.5 + 1))" should set the property value
+Fail	e.style['color'] = "oklch(calc(-0.5 * 3) calc(0.5 + 1) calc(-20deg * 2) / calc(-0.5 * 2))" should set the property value
+Fail	e.style['color'] = "oklch(calc(50%) 50% 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(200 calc(50%) 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(-200 calc(50%) 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(calc(50%) -100 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(none 0.2 calc(0.5))" should set the property value
+Fail	e.style['color'] = "oklch(none none none / none)" should set the property value
+Fail	e.style['color'] = "oklch(none none none)" should set the property value
+Fail	e.style['color'] = "oklch(0.2 none none / none)" should set the property value
+Fail	e.style['color'] = "oklch(none none none / 0.5)" should set the property value
+Fail	e.style['color'] = "oklch(0 0 0 / none)" should set the property value
+Fail	e.style['color'] = "lch(20% 80% 10/0.5)" should set the property value
+Fail	e.style['color'] = "oklch(20% 60% 10/0.5)" should set the property value
+Fail	e.style['color'] = "oklch(calc(infinity) 0 0)" should set the property value
+Fail	e.style['color'] = "oklch(0.5 calc(infinity) 0)" should set the property value
+Fail	e.style['color'] = "oklch(0.5 calc(-infinity) 0)" should set the property value
+Fail	e.style['color'] = "oklch(calc(NaN) 0 0)" should set the property value
+Fail	e.style['color'] = "oklch(calc(0 / 0) 0 0)" should set the property value
+Pass	e.style['color'] = "lab(calc(50 + (sign(1em - 10px) * 10)) 30 50 / 50%)" should set the property value
+Pass	e.style['color'] = "oklab(calc(0.5 + (sign(1em - 10px) * 0.1)) 0.3 0.5 / 50%)" should set the property value
+Pass	e.style['color'] = "lab(60 30 50 / calc(50% + (sign(1em - 10px) * 10%)))" should set the property value
+Pass	e.style['color'] = "oklab(0.6 0.3 0.5 / calc(50% + (sign(1em - 10px) * 10%)))" should set the property value
+Fail	e.style['color'] = "lch(calc(50 + (sign(1em - 10px) * 10)) 30 50deg / 50%)" should set the property value
+Fail	e.style['color'] = "oklch(calc(0.5 + (sign(1em - 10px) * 0.1)) 0.3 50deg / 50%)" should set the property value
+Fail	e.style['color'] = "lch(60 30 50deg / calc(50% + (sign(1em - 10px) * 10%)))" should set the property value
+Fail	e.style['color'] = "oklch(0.6 0.3 50deg / calc(50% + (sign(1em - 10px) * 10%)))" should set the property value
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-color/parsing/color-valid-lab.html b/Tests/LibWeb/Text/input/wpt-import/css/css-color/parsing/color-valid-lab.html
new file mode 100644
index 00000000000..81a42802286
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-color/parsing/color-valid-lab.html
@@ -0,0 +1,198 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Color Level 4: Parsing and serialization of colors using valid Lab notation</title>
+<link rel="help" href="https://drafts.csswg.org/css-color-4/#lab-colors">
+<link rel="help" href="https://drafts.csswg.org/css-color-4/#resolving-lab-lch-values">
+<link rel="help" href="https://drafts.csswg.org/css-color-4/#resolving-oklab-oklch-values">
+<link rel="help" href="https://drafts.csswg.org/css-color-4/#serializing-lab-lch">
+<link rel="help" href="https://drafts.csswg.org/css-color-4/#serializing-oklab-oklch">
+<script src="../../../resources/testharness.js"></script>
+<script src="../../../resources/testharnessreport.js"></script>
+<script src="../../../css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+tests = [
+    // lab()
+    ["lab(0 0 0)", "lab(0 0 0)"],
+    ["lab(0 0 0 / 1)", "lab(0 0 0)"],
+    ["lab(0 0 0 / 0.5)", "lab(0 0 0 / 0.5)"],
+    ["lab(20 0 10/0.5)", "lab(20 0 10 / 0.5)"],
+    ["lab(20 0 10/50%)", "lab(20 0 10 / 0.5)"],
+    ["lab(400 0 10/50%)", "lab(100 0 10 / 0.5)"],
+    ["lab(50 -160 160)", "lab(50 -160 160)"],
+    ["lab(50 -200 200)", "lab(50 -200 200)"],
+    ["lab(0 0 0 / -10%)", "lab(0 0 0 / 0)"],
+    ["lab(0 0 0 / 110%)", "lab(0 0 0)"],
+    ["lab(0 0 0 / 300%)", "lab(0 0 0)"],
+    ["lab(-40 0 0)", "lab(0 0 0)"],
+    ["lab(50 -20 0)", "lab(50 -20 0)"],
+    ["lab(50 0 -20)", "lab(50 0 -20)"],
+    ["lab(50% 50% -20%)", "lab(50 62.5 -25)"],
+    ["lab(50 -20% -20%)", "lab(50 -25 -25)"],
+    ["lab(calc(50 * 3) calc(0.5 - 1) calc(1.5) / calc(-0.5 + 1))", "lab(calc(150) calc(-0.5) calc(1.5) / calc(0.5))"],
+    ["lab(calc(-50 * 3) calc(0.5 + 1) calc(-1.5) / calc(-0.5 * 2))", "lab(calc(-150) calc(1.5) calc(-1.5) / calc(-1))"],
+    ["lab(calc(50%) 50% 0.5)", "lab(calc(50%) 62.5 0.5)"],
+    ["lab(200 calc(50%) 0.5)", "lab(100 calc(50%) 0.5)"],
+    ["lab(-200 calc(50%) 0.5)", "lab(0 calc(50%) 0.5)"],
+    ["lab(none 20 calc(0.5))", "lab(none 20 calc(0.5))"],
+
+    ["lab(none none none / none)", "lab(none none none / none)"],
+    ["lab(none none none)", "lab(none none none)"],
+    ["lab(20 none none / none)", "lab(20 none none / none)"],
+    ["lab(none none none / 0.5)", "lab(none none none / 0.5)"],
+    ["lab(0 0 0 / none)", "lab(0 0 0 / none)"],
+
+    ["lab(calc(infinity) 0 0)", "lab(calc(infinity) 0 0)"],
+    ["lab(50 calc(infinity) 0)", "lab(50 calc(infinity) 0)"],
+    ["lab(50 calc(-infinity) 0)", "lab(50 calc(-infinity) 0)"],
+    ["lab(calc(NaN) 0 0)", "lab(calc(NaN) 0 0)"],
+    ["lab(calc(0 / 0) 0 0)", "lab(calc(NaN) 0 0)"],
+
+    // oklab()
+    ["oklab(0 0 0)", "oklab(0 0 0)"],
+    ["oklab(0 0 0 / 1)", "oklab(0 0 0)"],
+    ["oklab(0 0 0 / 0.5)", "oklab(0 0 0 / 0.5)"],
+    ["oklab(0.2 0 0.1/0.5)", "oklab(0.2 0 0.1 / 0.5)"],
+    ["oklab(0.2 0 0.1/50%)", "oklab(0.2 0 0.1 / 0.5)"],
+    ["oklab(4 0 0.1/50%)", "oklab(1 0 0.1 / 0.5)"],
+    ["oklab(0.5 -1.6 1.6)", "oklab(0.5 -1.6 1.6)"],
+    ["oklab(0.5 -2 2)", "oklab(0.5 -2 2)"],
+    ["oklab(0 0 0 / -10%)", "oklab(0 0 0 / 0)"],
+    ["oklab(0 0 0 / 110%)", "oklab(0 0 0)"],
+    ["oklab(0 0 0 / 300%)", "oklab(0 0 0)"],
+    ["oklab(-0.4 0 0)", "oklab(0 0 0)"],
+    ["oklab(0.5 -2 0)", "oklab(0.5 -2 0)"],
+    ["oklab(0.5 0 -2)", "oklab(0.5 0 -2)"],
+    ["oklab(50% 50% -20%)", "oklab(0.5 0.2 -0.08)"],
+    ["oklab(0.5 -20% -20%)", "oklab(0.5 -0.08 -0.08)"],
+    ["oklab(calc(0.5 * 3) calc(0.5 - 1) calc(1.5) / calc(-0.5 + 1))", "oklab(calc(1.5) calc(-0.5) calc(1.5) / calc(0.5))"],
+    ["oklab(calc(-0.5 * 3) calc(0.5 + 1) calc(-1.5) / calc(-0.5 * 2))", "oklab(calc(-1.5) calc(1.5) calc(-1.5) / calc(-1))"],
+    ["oklab(calc(50%) 50% 0.5)", "oklab(calc(50%) 0.2 0.5)"],
+    ["oklab(200 calc(50%) 0.5)", "oklab(1 calc(50%) 0.5)"],
+    ["oklab(-200 calc(50%) 0.5)", "oklab(0 calc(50%) 0.5)"],
+    ["oklab(none 0.2 calc(0.5))", "oklab(none 0.2 calc(0.5))"],
+
+    ["oklab(none none none / none)", "oklab(none none none / none)"],
+    ["oklab(none none none)", "oklab(none none none)"],
+    ["oklab(0.2 none none / none)", "oklab(0.2 none none / none)"],
+    ["oklab(none none none / 0.5)", "oklab(none none none / 0.5)"],
+    ["oklab(0 0 0 / none)", "oklab(0 0 0 / none)"],
+
+    // These tests validate the ranges of lab() vs. oklab() components
+    ["lab(20% -50% 90%/0.5)", "lab(20 -62.5 112.5 / 0.5)"],
+    ["oklab(20% 70% -80%/0.5)", "oklab(0.2 0.28 -0.32 / 0.5)"],
+
+    ["oklab(calc(infinity) 0 0)", "oklab(calc(infinity) 0 0)"],
+    ["oklab(0.5 calc(infinity) 0)", "oklab(0.5 calc(infinity) 0)"],
+    ["oklab(0.5 calc(-infinity) 0)", "oklab(0.5 calc(-infinity) 0)"],
+    ["oklab(calc(NaN) 0 0)", "oklab(calc(NaN) 0 0)"],
+    ["oklab(calc(0 / 0) 0 0)", "oklab(calc(NaN) 0 0)"],
+
+    // lch()
+    ["lch(0 0 0deg)", "lch(0 0 0)"],
+    ["lch(0 0 0deg / 1)", "lch(0 0 0)"],
+    ["lch(0 0 0deg / 0.5)", "lch(0 0 0 / 0.5)"],
+    ["lch(100 230 0deg / 0.5)", "lch(100 230 0 / 0.5)"],
+    ["lch(20 50 20deg/0.5)", "lch(20 50 20 / 0.5)"],
+    ["lch(20 50 20deg/50%)", "lch(20 50 20 / 0.5)"],
+    ["lch(10 20 20deg / -10%)", "lch(10 20 20 / 0)"],
+    ["lch(10 20 20deg / 110%)", "lch(10 20 20)"],
+    ["lch(10 20 1.28rad)", "lch(10 20 73.3386)"],
+    ["lch(10 20 380deg)", "lch(10 20 20)"],
+    ["lch(10 20 -340deg)", "lch(10 20 20)"],
+    ["lch(10 20 740deg)", "lch(10 20 20)"],
+    ["lch(10 20 -700deg)", "lch(10 20 20)"],
+    ["lch(-40 0 0)", "lch(0 0 0)"],
+    ["lch(20 -20 0)", "lch(20 0 0)"],
+    ["lch(0 0 0 / 0.5)", "lch(0 0 0 / 0.5)"],
+    ["lch(10 20 20 / 110%)", "lch(10 20 20)"],
+    ["lch(10 20 -700)", "lch(10 20 20)"],
+    ["lch(50% 50% 20)", "lch(50 75 20)"],
+    ["lch(0.5 -20% -20)", "lch(0.5 0 340)"],
+    ["lch(calc(50 * 3) calc(0.5 - 1) calc(20deg * 2) / calc(-0.5 + 1))", "lch(calc(150) calc(-0.5) calc(40deg) / calc(0.5))"],
+    ["lch(calc(-50 * 3) calc(0.5 + 1) calc(-20deg * 2) / calc(-0.5 * 2))", "lch(calc(-150) calc(1.5) calc(-40deg) / calc(-1))"],
+    ["lch(calc(50%) 50% 0.5)", "lch(calc(50%) 75 0.5)"],
+    ["lch(200 calc(50%) 0.5)", "lch(100 calc(50%) 0.5)"],
+    ["lch(-200 calc(50%) 0.5)", "lch(0 calc(50%) 0.5)"],
+    ["lch(calc(50%) -100 0.5)", "lch(calc(50%) 0 0.5)"],
+    ["lch(none 20 calc(0.5))", "lch(none 20 calc(0.5))"],
+
+    ["lch(none none none / none)", "lch(none none none / none)"],
+    ["lch(none none none)", "lch(none none none)"],
+    ["lch(20 none none / none)", "lch(20 none none / none)"],
+    ["lch(none none none / 0.5)", "lch(none none none / 0.5)"],
+    ["lch(0 0 0 / none)", "lch(0 0 0 / none)"],
+
+    ["lch(calc(infinity) 0 0)", "lch(calc(infinity) 0 0)"],
+    ["lch(50 calc(infinity) 0)", "lch(50 calc(infinity) 0)"],
+    ["lch(50 calc(-infinity) 0)", "lch(50 calc(-infinity) 0)"],
+    ["lch(calc(NaN) 0 0)", "lch(calc(NaN) 0 0)"],
+    ["lch(calc(0 / 0) 0 0)", "lch(calc(NaN) 0 0)"],
+
+    // oklch()
+    ["oklch(0 0 0deg)", "oklch(0 0 0)"],
+    ["oklch(0 0 0deg / 1)", "oklch(0 0 0)"],
+    ["oklch(0 0 0deg / 0.5)", "oklch(0 0 0 / 0.5)"],
+    ["oklch(1 2.3 0deg / 0.5)", "oklch(1 2.3 0 / 0.5)"],
+    ["oklch(0.2 0.5 20deg/0.5)", "oklch(0.2 0.5 20 / 0.5)"],
+    ["oklch(0.2 0.5 20deg/50%)", "oklch(0.2 0.5 20 / 0.5)"],
+    ["oklch(0.1 0.2 20deg / -10%)", "oklch(0.1 0.2 20 / 0)"],
+    ["oklch(0.1 0.2 20deg / 110%)", "oklch(0.1 0.2 20)"],
+    ["oklch(0.1 0.2 1.28rad)", "oklch(0.1 0.2 73.3386)"],
+    ["oklch(0.1 0.2 380deg)", "oklch(0.1 0.2 20)"],
+    ["oklch(0.1 0.2 -340deg)", "oklch(0.1 0.2 20)"],
+    ["oklch(0.1 0.2 740deg)", "oklch(0.1 0.2 20)"],
+    ["oklch(0.1 0.2 -700deg)", "oklch(0.1 0.2 20)"],
+    ["oklch(-4 0 0)", "oklch(0 0 0)"],
+    ["oklch(0.2 -0.2 0)", "oklch(0.2 0 0)"],
+    ["oklch(0 0 0 / 0.5)", "oklch(0 0 0 / 0.5)"],
+    ["oklch(0.1 0.2 20 / 110%)", "oklch(0.1 0.2 20)"],
+    ["oklch(0.1 0.2 -700)", "oklch(0.1 0.2 20)"],
+    ["oklch(50% 50% 20)", "oklch(0.5 0.2 20)"],
+    ["oklch(0.5 -20% -20)", "oklch(0.5 0 340)"],
+    ["oklch(calc(0.5 * 3) calc(0.5 - 1) calc(20deg * 2) / calc(-0.5 + 1))", "oklch(calc(1.5) calc(-0.5) calc(40deg) / calc(0.5))"],
+    ["oklch(calc(-0.5 * 3) calc(0.5 + 1) calc(-20deg * 2) / calc(-0.5 * 2))", "oklch(calc(-1.5) calc(1.5) calc(-40deg) / calc(-1))"],
+    ["oklch(calc(50%) 50% 0.5)", "oklch(calc(50%) 0.2 0.5)"],
+    ["oklch(200 calc(50%) 0.5)", "oklch(1 calc(50%) 0.5)"],
+    ["oklch(-200 calc(50%) 0.5)", "oklch(0 calc(50%) 0.5)"],
+    ["oklch(calc(50%) -100 0.5)", "oklch(calc(50%) 0 0.5)"],
+    ["oklch(none 0.2 calc(0.5))", "oklch(none 0.2 calc(0.5))"],
+
+    ["oklch(none none none / none)", "oklch(none none none / none)"],
+    ["oklch(none none none)", "oklch(none none none)"],
+    ["oklch(0.2 none none / none)", "oklch(0.2 none none / none)"],
+    ["oklch(none none none / 0.5)", "oklch(none none none / 0.5)"],
+    ["oklch(0 0 0 / none)", "oklch(0 0 0 / none)"],
+
+    // These tests validate the ranges of lch() vs. oklch() lightness and chroma
+    ["lch(20% 80% 10/0.5)", "lch(20 120 10 / 0.5)"],
+    ["oklch(20% 60% 10/0.5)", "oklch(0.2 0.24 10 / 0.5)"],
+
+    ["oklch(calc(infinity) 0 0)", "oklch(calc(infinity) 0 0)"],
+    ["oklch(0.5 calc(infinity) 0)", "oklch(0.5 calc(infinity) 0)"],
+    ["oklch(0.5 calc(-infinity) 0)", "oklch(0.5 calc(-infinity) 0)"],
+    ["oklch(calc(NaN) 0 0)", "oklch(calc(NaN) 0 0)"],
+    ["oklch(calc(0 / 0) 0 0)", "oklch(calc(NaN) 0 0)"],
+
+    // calc(50% + (sign(1em - 10px) * 10%)) cannot be evaluated eagerly because font relative units are not yet known at parse time.
+    ["lab(calc(50 + (sign(1em - 10px) * 10)) 30 50 / 50%)", "lab(calc(50 + (10 * sign(1em - 10px))) 30 50 / 0.5)"],
+    ["oklab(calc(0.5 + (sign(1em - 10px) * 0.1)) 0.3 0.5 / 50%)", "oklab(calc(0.5 + (0.1 * sign(1em - 10px))) 0.3 0.5 / 0.5)"],
+    ["lab(60 30 50 / calc(50% + (sign(1em - 10px) * 10%)))", "lab(60 30 50 / calc(50% + (10% * sign(1em - 10px))))"],
+    ["oklab(0.6 0.3 0.5 / calc(50% + (sign(1em - 10px) * 10%)))", "oklab(0.6 0.3 0.5 / calc(50% + (10% * sign(1em - 10px))))"],
+
+    ["lch(calc(50 + (sign(1em - 10px) * 10)) 30 50deg / 50%)", "lch(calc(50 + (10 * sign(1em - 10px))) 30 50 / 0.5)"],
+    ["oklch(calc(0.5 + (sign(1em - 10px) * 0.1)) 0.3 50deg / 50%)", "oklch(calc(0.5 + (0.1 * sign(1em - 10px))) 0.3 50 / 0.5)"],
+    ["lch(60 30 50deg / calc(50% + (sign(1em - 10px) * 10%)))", "lch(60 30 50 / calc(50% + (10% * sign(1em - 10px))))"],
+    ["oklch(0.6 0.3 50deg / calc(50% + (sign(1em - 10px) * 10%)))", "oklch(0.6 0.3 50 / calc(50% + (10% * sign(1em - 10px))))"],
+];
+
+for (const test of tests) {
+    test_valid_value("color", test[0], test[1]);
+}
+
+</script>
+</body>
+</html>