.overlay {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(0, 0, 0, 0.7);
  transition: opacity 500ms;
  visibility: hidden;
  opacity: 0; 
}
.overlay:target {
  visibility: visible;
  opacity: 1;
}
.popup {
  margin: 250px auto;
  padding: 20px;
  background: #fff;
  border-radius: 15px;
  border-color: #AB3D63;
  width: 30%;
  position: relative;
  transition: all 5s ease-in-out;
  border: 2px solid #AB3D63;
}
.popup .close {
  position: absolute;
  top: 10px;
  right: 30px;
  transition: all 200ms;
  font-size: 30px;
  font-weight: bold;
  text-decoration: none;
  color: #AB3D63;
  background: #fff;
}