helps to create a mega menu

Hello,

I want to create a menu as the menu on the White House website (http://www.whitehouse.gov): Two columns of sub menus and a view in the third column. I installed the module Menu views, create my view. The view appears well on the top level menu.

Can you explain how to hide the view on the first level and how to display it on the second level next to the items of the second level? (I use nice-menu module). Can you tell me how to create my css file?

Thank you for your support.