#sign_up {
       
        position: relative;
        display: none;
    }

    #close_x { 
        width: 24px; height: 23px;
        overflow: hidden; line-height: 1000px;
        display: block;
        position: absolute; top: 5px; right: 5px;
        background-position: -387px -102px;
    }
    .sprited {
    background: url(stop.png) no-repeat;
    line-height: 1000px;
    overflow: hidden;
    display: block;
}