diff --git a/src/utils/colorPreference.ts b/src/utils/colorPreference.ts
index 3d971ad4..4103f456 100644
--- a/src/utils/colorPreference.ts
+++ b/src/utils/colorPreference.ts
@@ -4,7 +4,7 @@ export const prefersDarkMode = (cookieString: string): boolean => {
     const regex = /(?<=\bcolor_mode=)[^;]+/g;
     const match = regex.exec(cookieString);
     const cookie = match && JSON.parse(decodeURIComponent(match[0]));
-    const colorScheme: ColorScheme = cookie.color_mode ?? "auto";
+    const colorScheme: ColorScheme = cookie?.color_mode ?? "auto";
 
     if (colorScheme === "auto") {
         return window.matchMedia("(prefers-color-scheme: dark)").matches;