.actindicator_bg_layer {
    position: fixed;
    z-index: 10001;
    background: rgba(200, 200, 200, 0.6);
    height: 100%;
    width: 100%;
    top: 0;
    left: 0;
    display: none;
}
.actindicator_layer {
    width: 72px;
    height: 72px;
    display: none;
    position: fixed;
    _position: absolute; /* forIE6 */
    top: 50%;
    left: 50%;
    margin-top: -36px; /* harlf of height */
    margin-left: -36px; /* half of width */
    z-index: 10002;
}