modal.css

.w3-modal{
    z-index:3;
    display:none;
    padding-top:100px;
    position:fixed;
    left:0;
    top:0;
    width:100%;
    height:100%;
    overflow:auto;
    background-color:rgb(0,0,0);
    background-color:rgba(0,0,0,0.4)}


.w3-modal-content{margin:auto;
    background-color:#fff;
    position:relative;
    padding:0;
    outline:0;
    width:600px;
}

@media (max-width:600px){
    .w3-modal-content{
        margin:0 10px;width:auto!important}
        .w3-modal{padding-top:30px}
    }

@media (max-width:768px){
    .w3-modal-content{
        width:500px}
        .w3-modal{
            padding-top:50px}}

@media (min-width:993px){
    .w3-modal-content{width:900px}
    .w3-hide-large{display:none!important}
    .w3-sidebar.w3-collapse{display:block!important}}

.w3-btn, .w3-button {
    border: none;
    display: inline-block;
    padding: 8px 16px;
    vertical-align: middle;
    overflow: hidden;
    text-decoration: none;
    color: inherit;
    background-color: inherit;
    text-align: center;
    cursor: pointer;
    white-space: nowrap;
}

.w3-display-topright {
    position: absolute;
    right: 0px;
    top: 0px;
}

.w3-btn, .w3-button {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.tab {
  overflow: hidden;
  border: 1px solid #ccc;
  background-color: #f1f1f1;
}
/* Style the buttons inside the tab */
.tab button {
  background-color: inherit;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 14px 16px;
  transition: 0.3s;
  font-size: 17px;
}

/* Change background color of buttons on hover */
.tab button:hover {
  background-color: #ddd;
}

/* Create an active/current tablink class */
.tab button.active {
  background-color: #ccc;
}

/* Style the tab content */
.tabcontent {
  display: none;
  padding: 6px 12px;
  border: 1px solid #ccc;
  border-top: none;
}