Responsive Navbar with Multilevel Dropdowns

Create a responsive navbar with 5 menu items, each with an icon. The navbar should include multilevel dropdowns for some menu items, with icons for the dropdown items as well. On smaller screens like iPads and mobile devices, the navbar should transform into a hamburger menu. The hamburger menu should display all options, including multilevel dropdowns. Additionally, when the hamburger menu is clicked, it should smoothly animate and change into a 'cross' (X) icon, and toggle back when clicked again.