.modal{
     display: none; /* Hidden by default */
     position: fixed; /* Stay in place */
     z-index: 1; /* Sit on top */
     padding-top: 100px; /* Location of the box */
     left: 0;
     top: 0;
     width: 100%; /* Full width */
     height: 100%; /* Full height */
     overflow: auto; /* Enable scroll if needed */
     background-color: rgb(0,0,0); /* Fallback color */
     background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}
.modal_content{
     background-color: #fefefe;
     margin: auto;
     padding: 20px;
     border: 1px solid #888;
     width: 80%;
}