popup menus

On the responsive design on a mobile device (e.g. iPhone), the account popup menu fills the screen, so there is no way to get rid of it. How hard would it be to add a close link (e.g. a font awesome circled X button) located top right of the popup box to close it?

I always run into this problem on light styles when the navigation bar is dark (e.g., #646464), but the sub-navigation bar is light (e.g., #F0F0F0). When the username, Inbox, or Alert dropdowns are selected (when you're on /account), the text is unreadable: I know what the problem is. It's...