/* CSS Document */
H1    { font-size: 8pt }
H2    { font-size: 5pt }
H3    { font-size: 10pt }
H4    { font-size: 9pt; color: #333333; font-family: Verdana, Arial, Helvetica, sans-serif; font-weight: none }
TABLE H1 { font-size: 8pt; color: #339933; font-family: Arial, Helvetica, sans-serif; font-weight: normal }

#mydiv {   
    position:absolute;   
    top: 50%;   
    left: 50%;   
    width:380px;   
    height:380px;   
    margin-top: -190px; /*set to a negative number 1/2 of your height*/  
    margin-left: -190px; /*set to a negative number 1/2 of your width*/        
}