Hello @neha
On your iPhone, is the operating system iOS version 9 or less?
If so, that would explain the issue, as the CSS grid is only compatible with iOS version 10 and above.
You should be able to update your iPhone to iOS 12 or 13 for compatibility with modern CSS styling.
The user icon does display as an arrow when you view your site as a not logged in user. It is only the user icon when you are logged in to your site so you and your site’s customers can distinguish between signed in or out.