Zurb Foundation 6 fix for WordPress default menu widget.(This is a fix used in Ole Fredrik Lie's FoundationPress https://github.com/olefredrik/FoundationPress)

_footer-2.scss

// As of Zurb Foundation 6.4 the style below should be used
div.footer-container {
	ul.menu {
		flex-direction: column;
		li {
			a {
				display: block;//Optional
				padding: 0;
				margin: 0;
				line-height: 1.6rem;
			}
		}		
	}
}

_footer.scss

// Zurb Foundation 6 fix for WordPress default menu widget.
#footer-container {
	ul.menu {
		li {
			display: block;
			a {
				display: inline;
				padding: 0;
				margin: 0;
				line-height: 1.6rem;
			}
		}		
	}
}