diff --git a/packages/frontend/src/components/layouts/search/Search.tsx b/packages/frontend/src/components/layouts/search/Search.tsx
index d5485406..5b006447 100644
--- a/packages/frontend/src/components/layouts/search/Search.tsx
+++ b/packages/frontend/src/components/layouts/search/Search.tsx
@@ -15,6 +15,7 @@ export const Search = ({ className }: SearchProps) => {
 
   const handleSubmit = (event: FormEvent<HTMLFormElement>) => {
     event.preventDefault();
+    if (!stockName) return;
     refetch();
   };
 
diff --git a/packages/frontend/src/pages/stock-detail/hooks/useChart.ts b/packages/frontend/src/pages/stock-detail/hooks/useChart.ts
index 7b26f1d3..b7c22836 100644
--- a/packages/frontend/src/pages/stock-detail/hooks/useChart.ts
+++ b/packages/frontend/src/pages/stock-detail/hooks/useChart.ts
@@ -44,7 +44,11 @@ export const useChart = ({
   const containerInstance = containerRef.current;
 
   const { theme } = useContext(ThemeContext);
-  const graphTheme = theme === 'light' ? lightTheme : darkTheme;
+  const graphTheme = theme
+    ? theme === 'light'
+      ? lightTheme
+      : darkTheme
+    : lightTheme;
 
   useEffect(() => {
     if (!containerInstance) return;