Show Mobile Menu On Desktop

@skynet : Happy Holidays.
To enable mobile menu on desktop add the following additional css.

#primary,
#secondary,
#site-generator .copyright, 
#site-generator .powered {
	display: block;
	float: none;
	width: 100%;
}

#nav-below {
	border-bottom: 1px solid #ccc;
}

#access ul.menu a,
#access-secondary ul.menu a,
#access-footer ul.menu a {
	font-size: 15px;
	line-height: 3em;
		padding: 0 20px;
		text-align: left;
}
#access ul.menu ul a, 
#access-secondary ul.menu ul a,
#access-footer ul.menu ul a {
	font-size: 15px;
	line-height: 1.66em;
}

/* Menu */
.menu-access-wrap {
	background-color: #3d3d3d;
	clear: both;
	display: block;
	padding: 0;
	position: relative;
}
#access,
#access ul.menu ul a,
#access-secondary,
#access-secondary ul.menu a,
#access-secondary ul.menu ul a {
	background: none;
	background-color: #3d3d3d;
	color: #eee;
	border: none;
}
#access ul.menu li:hover > a,
#access ul.menu a:focus,
#access-secondary ul.menu li:hover > a,
#access-secondary ul.menu a:focus,
#access-footer ul.menu a:hover,
#access-footer ul.menu a:focus {
	background: none;
	background-color: #333;
	color: #fff;
}
#mobile-footer-menu {
	padding: 0;
}
.site-header-menu,
.site-footer-menu {
	display: none;
	width: 100%;
}
.mobile-menu-anchor {
	display: inline-block;
}
.primary-menu-open #site-header-menu-primary,
.secondary-menu-open #site-header-menu-secondary,
.footer-menu-open #site-footer-mobile-menu {
    display: block;
}
#access ul.menu li, 
#access-secondary ul.menu li,
#access-footer ul.menu li {
	border-left: none;
	float: none;
}
.menu-access-wrap #access ul.menu li,
.menu-access-wrap #access-secondary ul.menu li,
.menu-access-wrap #access-footer ul.menu li {
	border-bottom: 1px dotted #ccc;
}
.menu-access-wrap #access .toggled-on li:first-child,
.menu-access-wrap #access-secondary .toggled-on li:first-child,
.menu-access-wrap #access-footer .toggled-on li:first-child {
	margin-top: 1px;
}
.site-header-menu #access .menu-item-has-children > a, 
.site-header-menu #access .page_item_has_children > a,
.site-header-menu #access-secondary .menu-item-has-children > a,
.site-footer-menu #access-footer .menu-item-has-children > a {
    margin-right: 45px;
    padding-right: 0
}
#access ul.menu ul,
#access-secondary ul.menu ul,
#access-footer ul.menu ul {
	position: relative;
	box-shadow: none;
}
#access ul.menu ul,
#access ul.menu ul ul,
#access-secondary ul.menu ul,
#access-secondary ul.menu ul ul,
#access-footer ul.menu ul,
#access-footer ul.menu ul ul {
    left: auto;
    position: relative;
    top: auto;
    width: 100%;
}
#access ul.menu ul li:hover > ul,
#access ul.menu ul li.focus > ul,
#access-secondary ul.menu ul li:hover > ul,
#access-secondary ul.menu ul li.focus > ul,
#access-footer ul.menu ul li:hover > ul,
#access-footer ul.menu ul li.focus > ul {
	left: auto;
	top: auto;
	width: 100%;
}
#access ul.menu ul a, 
#access-secondary ul.menu ul a,
#access-footer ul.menu ul a {
	width: auto;
	padding-left: 30px;
}
#access ul.menu ul ul a, 
#access-secondary ul.menu ul ul a,
#access-footer ul.menu ul ul a {
	padding-left: 40px;
}
#access ul.menu ul ul ul a, 
#access-secondary ul.menu ul ul ul a,
#access-footer ul.menu ul ul ul a {
	padding-left: 50px;
}
#access ul.menu ul ul ul ul a, 
#access-secondary ul.menu ul ul ul ul a,
#access-footer ul.menu ul ul ul ul a {
	padding-left: 60px;
}
.site-header-menu #access ul ul,
.site-header-menu #access-secondary ul ul,
.site-footer-menu #access-footer ul ul {
	display: none;
}
.site-header-menu #access ul .toggled-on,
.site-header-menu #access-secondary ul .toggled-on,
.site-footer-menu #access-footer ul .toggled-on {
	display: block;
}
.dropdown-toggle {
	background-color: transparent;
	border: 0;
	border-radius: 0;
	color: #eee;
	content: "";
	cursor: pointer;
	display: block;
	height: 45px;
	padding: 0;
	position: absolute;
	right: 0;
	text-transform: none;
	top: 0;
	width: 45px;
}
.dropdown-toggle:after {
	border: 0 solid #eee;
	border-left-width: 1px;
	content: "\f431";
	font-size: 24px;
	left: 1px;
	position: relative;
	width: 45px;
}
.dropdown-toggle:hover,
.dropdown-toggle:focus {
	background-color: #333;
}
.dropdown-toggle:focus {
	outline: thin dotted;
	outline-offset: -1px;
}
.dropdown-toggle:focus:after {
	border-color: transparent;
}
.dropdown-toggle.toggled-on:after {
	content: "\f432";
}	
.one-menu .menu-access-wrap,
#colophon .menu-access-wrap {
	text-align: center;
}
.one-menu #mobile-header-left-menu {
	float: none;
	transition-property: left, right;
		transition-duration: 3s, 3s;
		transition-delay: 0s, 1s;
}
.mobile-footer-nav-open #colophon .menu-access-wrap {
    left: 0;
    position: absolute;
    top: 0;
    z-index: 999;
}
#mobile-header-right-menu .mobile-menu-text {
	float: left;
}

Let me know if this resolves your issue.

Regards,
Tikaram

@skynet : It will not have any impact on page loading time. Let me know if you have any further issues.

Regards,
Tikaram