diff --git a/vitest.setup.ts b/vitest.setup.ts
index f149f27..2a9307e 100644
--- a/vitest.setup.ts
+++ b/vitest.setup.ts
@@ -1 +1,24 @@
 import "@testing-library/jest-dom/vitest";
+
+// Polyfill localStorage for jsdom if not available
+if (typeof localStorage === "undefined") {
+  const store: Record<string, string> = {};
+  (global as any).localStorage = {
+    getItem: (key: string) => store[key] || null,
+    setItem: (key: string, value: string) => {
+      store[key] = String(value);
+    },
+    removeItem: (key: string) => {
+      delete store[key];
+    },
+    clear: () => {
+      for (const key in store) {
+        delete store[key];
+      }
+    },
+    key: (index: number) => Object.keys(store)[index] || null,
+    get length() {
+      return Object.keys(store).length;
+    },
+  };
+}