Fix z index of header to avoid conflict with ads

Author: wajeshubham

components/SigninButton.tsx

@@ -8,7 +8,11 @@ const SigninButton = () => {
 
   return (
     <>
-      <Button data-testid="signin-btn" onClick={loginWithGoogle}>
+      <Button
+        className="z-20"
+        data-testid="signin-btn"
+        onClick={loginWithGoogle}
+      >
         <GoogleIcon className="inline-flex mr-2" />
         Sign in/up
       </Button>

layout/Header.tsx

@@ -11,12 +11,12 @@ const Header = () => {
   return (
     <header data-testid="header" className="w-full">
       <nav className="w-full h-20 flex justify-between items-center max-w-7xl mx-auto px-4 sm:px-8 lg:px-12">
-        <div className="flex justify-start items-center w-1/2 flex-shrink-0">
+        <div className="flex z-40 justify-start items-center w-1/2 flex-shrink-0">
           <Link className="inline-flex items-center" href={"/"}>
             <Logo />
           </Link>
         </div>
-        <div className="flex justify-end gap-4 items-center w-1/2 flex-shrink-0">
+        <div className="flex z-40 justify-end gap-4 items-center w-1/2 flex-shrink-0">
           <ThemeToggle />
           {user?.uid ? (
             <>