chore: fix layout index.css

Author: Hyogyeong Shin

src/index.css

@@ -32,12 +32,14 @@ body {
   min-width: 430px;
   width: 100%;
   height: 100vh;
-  /* overflow: hidden; */
+  overflow-x: hidden;
   @apply mx-auto flex flex-col;
   @apply bg-gray-100 text-mainText dark:bg-gray-900 dark:text-white;
 }
 
 #root {
+  display: flex;
+  justify-content: center;
   height: 100%;
   width: 100%;
 }