Fix shadow overlay

Author: gultyayev

src/components/MainLayout/components/Header.tsx

@@ -43,7 +43,7 @@ export default function Header() {
   };
 
   return (
-    <AppBar position="static">
+    <AppBar position="relative">
       <Toolbar>
         <Typography variant="h6" className={classes.title}>
           <Link className={classes.homeLink} to="/">My Store!</Link>