A horizontal slide out menu with a grid-like thumbnail layout for the submenu. With media query examples for smaller devices. The menu slides out from the top when a main menu item is clicked and the sub-items fade in. When clicking on another item, the height of the submenu will adjust and the content will fade in and out while switching.Some media query examples show how to make the menu responsive and change the view to a touch-friendly vertically stacked navigation.
CSS Menus Responsive