From d0b26a4dcebda882b195b0699a065dc59f9278c2 Mon Sep 17 00:00:00 2001
From: KumJungMin <37934668+KumJungMin@users.noreply.github.com>
Date: Sat, 19 Sep 2026 22:43:48 +0900
Subject: [PATCH 1/2] feat: preserve keyframe selector casing in error messages

---
 src/rules/no-duplicate-keyframe-selectors.js        |  8 ++++++--
 tests/rules/no-duplicate-keyframe-selectors.test.js | 12 ++++++------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/rules/no-duplicate-keyframe-selectors.js b/src/rules/no-duplicate-keyframe-selectors.js
index a51ff808..778dee03 100644
--- a/src/rules/no-duplicate-keyframe-selectors.js
+++ b/src/rules/no-duplicate-keyframe-selectors.js
@@ -66,16 +66,20 @@ export default /** @satisfies {DuplicateKeyframeSelectorRuleDefinition} */ ({
 				// @ts-ignore - children is a valid property for prelude
 				node.prelude.children.forEach(selector => {
 					const value = [];
+					const rawValue = [];
 
 					selector.children.forEach(component => {
 						if (component.type === "Percentage") {
-							value.push(`${component.value}%`);
+							const percentage = `${component.value}%`;
+							value.push(percentage);
+							rawValue.push(percentage);
 						} else if (component.type === "TypeSelector") {
 							value.push(component.name.toLowerCase());
+							rawValue.push(component.name);
 						}
 					});
 
-					const selectorValue = value.join(" ");
+					const selectorValue = rawValue.join(" ");
 					const key = value
 						.map(
 							selectorPart =>
diff --git a/tests/rules/no-duplicate-keyframe-selectors.test.js b/tests/rules/no-duplicate-keyframe-selectors.test.js
index 272b1a6e..1dcd93e1 100644
--- a/tests/rules/no-duplicate-keyframe-selectors.test.js
+++ b/tests/rules/no-duplicate-keyframe-selectors.test.js
@@ -215,7 +215,7 @@ ruleTester.run("no-duplicate-keyframe-selectors", rule, {
 			errors: [
 				{
 					messageId: "duplicateKeyframeSelector",
-					data: { selector: "from" },
+					data: { selector: "From" },
 					line: 3,
 					column: 5,
 					endLine: 3,
@@ -231,7 +231,7 @@ ruleTester.run("no-duplicate-keyframe-selectors", rule, {
 			errors: [
 				{
 					messageId: "duplicateKeyframeSelector",
-					data: { selector: "from" },
+					data: { selector: "FROM" },
 					line: 3,
 					column: 5,
 					endLine: 3,
@@ -265,7 +265,7 @@ ruleTester.run("no-duplicate-keyframe-selectors", rule, {
 			errors: [
 				{
 					messageId: "duplicateKeyframeSelector",
-					data: { selector: "to" },
+					data: { selector: "TO" },
 					line: 4,
 					column: 5,
 					endLine: 4,
@@ -624,7 +624,7 @@ ruleTester.run("no-duplicate-keyframe-selectors", rule, {
 			errors: [
 				{
 					messageId: "duplicateKeyframeSelector",
-					data: { selector: "entry 0%" },
+					data: { selector: "Entry 0%" },
 					line: 2,
 					column: 15,
 					endLine: 2,
@@ -742,7 +742,7 @@ ruleTester.run("no-duplicate-keyframe-selectors", rule, {
 			errors: [
 				{
 					messageId: "duplicateKeyframeSelector",
-					data: { selector: "from" },
+					data: { selector: "From" },
 					line: 3,
 					column: 5,
 					endLine: 3,
@@ -750,7 +750,7 @@ ruleTester.run("no-duplicate-keyframe-selectors", rule, {
 				},
 				{
 					messageId: "duplicateKeyframeSelector",
-					data: { selector: "to" },
+					data: { selector: "TO" },
 					line: 5,
 					column: 5,
 					endLine: 5,

From 963d3dcbe0d87cbcd7a7cdbb773a77aeb9bf0f11 Mon Sep 17 00:00:00 2001
From: KumJungMin <37934668+KumJungMin@users.noreply.github.com>
Date: Mon, 21 Sep 2026 08:14:08 +0900
Subject: [PATCH 2/2] refactor: lowercase keyframe selectors when computing
 comparison keys

---
 src/rules/no-duplicate-keyframe-selectors.js | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/src/rules/no-duplicate-keyframe-selectors.js b/src/rules/no-duplicate-keyframe-selectors.js
index 778dee03..fd0ba11e 100644
--- a/src/rules/no-duplicate-keyframe-selectors.js
+++ b/src/rules/no-duplicate-keyframe-selectors.js
@@ -66,26 +66,21 @@ export default /** @satisfies {DuplicateKeyframeSelectorRuleDefinition} */ ({
 				// @ts-ignore - children is a valid property for prelude
 				node.prelude.children.forEach(selector => {
 					const value = [];
-					const rawValue = [];
 
 					selector.children.forEach(component => {
 						if (component.type === "Percentage") {
-							const percentage = `${component.value}%`;
-							value.push(percentage);
-							rawValue.push(percentage);
+							value.push(`${component.value}%`);
 						} else if (component.type === "TypeSelector") {
-							value.push(component.name.toLowerCase());
-							rawValue.push(component.name);
+							value.push(component.name);
 						}
 					});
 
-					const selectorValue = rawValue.join(" ");
+					const selectorValue = value.join(" ");
 					const key = value
-						.map(
-							selectorPart =>
-								keyframeSelectorAliases.get(selectorPart) ??
-								selectorPart,
-						)
+						.map(selectorPart => {
+							const part = selectorPart.toLowerCase();
+							return keyframeSelectorAliases.get(part) ?? part;
+						})
 						.join(" ");
 
 					if (seen.has(key)) {