Update CSS classes in web pages

The CSS classes used across different web pages in the web application have been updated. This change mainly consists of adjustments to spacing on various elements to improve the visual layout. The alterations should enhance the readability and user experience of the mentioned pages.

apps/web/app/(marketing)/layout.tsx

@@ -9,7 +9,7 @@ async function SiteLayout(props: React.PropsWithChildren) {
   const user = await getUser();
 
   return (
-    <>
+    <div className={'flex flex-col space-y-8'}>
       <SiteHeader user={user} />
 
       {props.children}
@@ -17,7 +17,7 @@ async function SiteLayout(props: React.PropsWithChildren) {
       <Separator />
 
       <SiteFooter />
-    </>
+    </div>
   );
 }