modified Reponsive Menu CSS

/* Responsive Navigation
---------------------------------------------------------------------------------------------------- */

/* Standard Navigation
--------------------------------------------- */

nav {
	clear: both;
}

/* Navigation toggles
--------------------------------------------- */

.sub-menu-toggle,
.c-hamburger {
	display: none;
	visibility: hidden;
}

/* Navigation toggles - Ensure Menu Displays when Scaled Up
--------------------------------------------- */

@media only screen and (min-width: 768px) {

	nav {
		display: block !important;
	}
}

/* Navigation toggles - Mobile (Change max width as you see fit)
--------------------------------------------- */

@media only screen and (max-width: 767px) {
	.c-hamburger,
	.sub-menu-toggle {
		display: block;
		font-size: 20px;
		font-size: 2rem;
		font-weight: 700;
		margin: 0 auto;
		overflow: hidden;
		padding: 20px;
		padding: 2rem;
		text-align: center;
		visibility: visible;
	}

	button.sub-menu-toggle {
		background-color: transparent;
		color: #999;
	}

	.sub-menu-toggle {
		padding: 18px;
		padding: 1.8rem;
		position: absolute;
		right: 0;
		top: 0;
	}


	.sub-menu-toggle:before {
		content: "+";
	}

	.sub-menu-toggle.is-active:before {
		content: "-";
	}

	nav {
		display: none;
		position: relative;
	}

	.genesis-nav-menu .menu-item {
		background-color: #f5f5f5;
		display: block;
		position: relative;
		text-align: left;
	}

	.genesis-nav-menu .menu-item:hover {
		position: relative;
	}

	.genesis-nav-menu .sub-menu {
		clear: both;
		display: none;
		opacity: 1;
		position: static;
		width: 100%;
	}

	.genesis-nav-menu .sub-menu a {
		border-left: 0;
		position: relative;
		width: auto;
	}

	.genesis-nav-menu .sub-menu .sub-menu {
		margin: 0;
	}

	.genesis-nav-menu .sub-menu .sub-menu a {
		background-color: #f5f5f5;
		padding-left: 30px;
	}

	.genesis-nav-menu .sub-menu .sub-menu .sub-menu a {
		background-color: #fff;
		padding-left: 40px;
	}

	.nav-primary a:hover,
	.nav-primary .current-menu-item > a {
		color: #333;
	}

}