Paste this before </syle> or after <style>

#fade {
    display:none;
    background:#000;
    position:fixed;
    left:0; top:0;
    width:100%;
    height:100%;
    opacity:.80;
    z-index:9999; }
.popup_block {
    display:none;
    background:#fff;
    padding:10px;
    border:10px solid #f2e7e2;
    float:left;
    font-size:10;
    position:fixed;
    top:50%; left:50%;
    z-index:99999;
    -webkit-box-shadow: 0px 0px 20px #000; -moz-box-shadow: 0px 0px 20px #000; box-shadow: 0px 0px 20px #000; -webkit-border-radius: 5px; -moz-border-radius: 5px; border-radius: 5px; }
img.btn_close {
    float:right;
    margin:3px 3px 0px 0px; }
*html #fade { position:absolute; }
*html .popup_block { position:absolute; }