Need help centering my css code

[agminco]

1) CODE TITLE: Hopeology css

2) AUTHOR NAME/NOTES: Anne McCullough

3) DESCRIPTION: Drop down menu css file

4) URL TO CODE:

or, ATTACHED BELOW (see #3 in guidelines below):

#dropmenu
{	margin: 0;
	padding: 0;
	z-index: 0;
	float:left;
	width: 60em;
	margin: auto;
	text-align: center
	}

#dropmenu ul
{
	clear: left;
	float: right;
	right: 50%;
	position: relative;
	text-align: center}

#dropmenu li
{	margin: 0;
	padding: 0; 
	list-style: none;
	background-color: #909090;
	float: left;
	font: bold 11px tempus sans itc;
	text-align: center;
	position: relative;
	left: 50%}

#dropmenu li a
{	display: block;
	margin: 0 0px 0 0;
	padding: 0px 0px;
	background: #9CBCE5;
	color: #FFF;
	text-align: center;
	text-decoration: none}

#dropmenu li a:hover
{	background: #49A3FF}

#dropmenu div
{	position: absolute;
	visibility: hidden;
	margin: 0;
	padding: 0;
	background: #EAEBD8;
	border: 1px solid #5970B2}

	#dropmenu div a
	{	position: relative;
		display: block;
		margin: 0;
		padding: 5px 10px;
		width: auto;
		white-space: nowrap;
		text-align: center;
		text-decoration: none;
		background: #EAEBD8;
		color: #2875DE;
		font: 14px tempus sans itc;
		font-weight:bold;
		text-decoration: underline}

	#dropmenu div a:hover
	{	background: #49A3FF;
		color: #FFF}