menu, navigation

Need horizontal menu (unlimited points), when you click (or hover) under it opens a block with vertical submenus (unlimited points), and when you click (or hover) on the submenu items should open the unit with the text.
For example, open a submenu there , maybe there's a simpler implementation, the main thing that worked in all browsers, but if you reduce the size of the screen, the points were transferred and not left outside the screen.