HTML Custom pop-up modal responsive

 <div id="popup1" class="overlay">
         <div class="popup">
            <h5>User Details of</h5>
            <a class="close" href="#">&times;</a>
            <div class="content">
               <div class="modal-body">
                  <ul class="list-group">
                     <li class="list-group-item"><b>Weight:</b></li>
                     <li class="list-group-item"><b>University:</b></li>
                     <li class="list-group-item"><b>Ip:</b></li>
                  </ul>
               </div>
            </div>
         </div>
      </div>

`

1. Stylesheet

`
.box {
width: 40%;
margin: 0 auto;
background: rgba(255, 255, 255, 0.2);
padding: 35px;
border: 2px solid #fff;
border-radius: 20px/50px;
background-clip: padding-box;
text-align: center;
}

.overlay {
position: fixed;
top: 0;
bottom: 0;
left: 0;
right: 0;
background: rgba(0, 0, 0, 0.7);
transition: opacity 500ms;
visibility: visible;
opacity: 1;
z-index: 1;
}

.overlay:target {
visibility: visible;
opacity: 1;
}

.popup {
margin: 70px auto;
padding: 20px;
background: #fff;
border-radius: 5px;
width: 30%;
position: relative;
transition: all 5s ease-in-out;
}

.popup h2 {
margin-top: 0;
color: #333;
font-family: Tahoma, Arial, sans-serif;
}

.popup .close {
position: absolute;
top: 20px;
right: 30px;
transition: all 200ms;
font-size: 30px;
font-weight: bold;
text-decoration: none;
color: #333;
}

.popup .close:hover {
color: #06D85F;
}

.popup .content {
max-height: 30%;
overflow: auto;
}

@media screen and (max-width: 700px) {
.box {
width: 70%;
}

.popup {
width: 70%;
}
}
`