Navigation Margins

Hi Everyone,

I am having difficulty with the margins underneath my navigation bar. When I try and change the margin so the header is below the nav bar, the drop down menus don’t work for some reason. Here is the code I am using:

#nav {
	width: 100%;
	float: left;
	margin: 0 0 6em 0;
	background-color: #ffffff;
	text-transform: lowercase;
	opacity:0.7;
	clear: both;
	overflow: hidden;

}

#nav .wrap {
	color: #777;
	font-family: 'Verdana', arial, sans-serif;
	letter-spacing: 2px;
	margin: 0 auto;
	width: 600px;

}

#nav ul {
	float: left;
	width: 100%;
}

#nav li {
	float: left;
	list-style-type: none;

}

#nav li a {
	color: #336699;
	display: block;
	font-size: 13px;
	padding: 12px 15px 14px;
	text-decoration: none;
		position: relative;
}

#nav li a:hover,
#nav li a:active,
#nav .current_page_item a,
#nav .current-cat a,
#nav .current-menu-item a {
	color: #ccc;
}

#nav li li a,
#nav li li a:link,
#nav li li a:visited {
	background-color: #fff;
	border: none;
	border-top-width: 0;
	color: #336699;
	font-size: 11px;
	letter-spacing: 1px;
	padding: 5px 10px;
	position: relative;
	text-transform: none;
	width: 138px;
}

#nav li li a:hover,
#nav li li a:active {
	background-color: #ccc;
}

#nav li ul {
	height: auto;
	left: -9999px;
	position: absolute;
	width: 160px;
	z-index: 9999;
}

#nav li ul a {
	width: 140px;
}

#nav li ul ul {
	margin: -33px 0 0 159px;
}

#nav li:hover>ul,
#nav li.sfHover ul {
	left: auto;
}

Does anyone have any insight on this? My page is located here

Thank you!