From 46c0de15c8741e5ee937fff43ac6acd9526dd71b Mon Sep 17 00:00:00 2001
From: andjsrk <andjsrk0213@gmail.com>
Date: Thu, 13 Mar 2025 15:49:25 +0900
Subject: [PATCH 1/3] Match runtime behavior to the type definition

---
 packages/css/src/style.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/css/src/style.ts b/packages/css/src/style.ts
index d2c417a1f..be0c46f75 100644
--- a/packages/css/src/style.ts
+++ b/packages/css/src/style.ts
@@ -27,7 +27,11 @@ function composedStyle(rules: Array<StyleRule | ClassNames>, debugId?: string) {
   const classList = [];
   const styleRules = [];
 
-  for (const rule of rules) {
+  // `flat(Infinity)` fails to compile because of TS2589
+  const flattenedRules = rules.flat(Infinity as 20) as Array<
+    StyleRule | string
+  >;
+  for (const rule of flattenedRules) {
     if (typeof rule === 'string') {
       classList.push(rule);
     } else {

From 51826cac03e8968aedfc6d80ce573702c8ebfeb5 Mon Sep 17 00:00:00 2001
From: andjsrk <andjsrk0213@gmail.com>
Date: Thu, 13 Mar 2025 16:10:57 +0900
Subject: [PATCH 2/3] Add changeset

---
 .changeset/dry-rabbits-grow.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/dry-rabbits-grow.md

diff --git a/.changeset/dry-rabbits-grow.md b/.changeset/dry-rabbits-grow.md
new file mode 100644
index 000000000..4c0b204fb
--- /dev/null
+++ b/.changeset/dry-rabbits-grow.md
@@ -0,0 +1,5 @@
+---
+'@vanilla-extract/css': patch
+---
+
+Fix runtime behavior to match the type definition

From a95d74bd76cefcab723e48b9c39f9e3ae0b952bc Mon Sep 17 00:00:00 2001
From: andjsrk <andjsrk0213@gmail.com>
Date: Thu, 13 Mar 2025 16:34:45 +0900
Subject: [PATCH 3/3] Fix code more appropriately

`dudupeAndJoinClassList(classList)` is on below and will handle `ClassNames`
---
 packages/css/src/style.ts | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/packages/css/src/style.ts b/packages/css/src/style.ts
index be0c46f75..39a4bc2ea 100644
--- a/packages/css/src/style.ts
+++ b/packages/css/src/style.ts
@@ -27,15 +27,11 @@ function composedStyle(rules: Array<StyleRule | ClassNames>, debugId?: string) {
   const classList = [];
   const styleRules = [];
 
-  // `flat(Infinity)` fails to compile because of TS2589
-  const flattenedRules = rules.flat(Infinity as 20) as Array<
-    StyleRule | string
-  >;
-  for (const rule of flattenedRules) {
-    if (typeof rule === 'string') {
-      classList.push(rule);
-    } else {
+  for (const rule of rules) {
+    if (typeof rule !== 'string' && !Array.isArray(rule)) {
       styleRules.push(rule);
+    } else {
+      classList.push(rule);
     }
   }