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}