.dialog-back-panel {
  z-index:10000;
  display:none;
  position:fixed;
  top:0;
  left:0;
  width:100%;
  height:100%;
  background-color:rgba(59,59,59, 0.8);
  text-align:center;
}

.dialog-back-panel .close_overlay {
  z-index: 10001;
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: transparent;
  text-indent: -9999px;
}

.dialog-back-panel .dialog-content {
    position:relative;
    /*top:5%;*/
    width:70%;
    height:auto;
    background-color: #fff;
    /* rounded corners */
    -moz-border-radius: 5px;
    -webkit-border-radius: 5px;
    border-radius: 5px;
    z-index:10010;
    margin: 5% auto;
    padding:20px;
    box-sizing:border-box;
}

/* 'target' pseudo-class does the job */
.dialog-back-panel:target { display: block; }