Remove underline from hamburger menu toggle on mobile

_sass/foundation-components/_top-bar.scss

@@ -235,6 +235,7 @@ $topbar-dropdown-arrows: true !default; //Set false to remove the \00bb >> text
           padding: 0 $topbar-link-padding;
           height: $topbar-height;
           line-height: $topbar-height;
+          border: none;
         }
 
         // Adding the class "menu-icon" will add the 3-line icon people love and adore.