overlay.css

.overlay {
  display: block !important;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  position: fixed;
  padding: 20px;  
  left: 50%;
  top: 60px;  
  transform: translate(-50%, 0);
  width: 98%;  
  min-height: 100px;  
   max-height: calc(98% - 60px);
  z-index: 999;
  overflow: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  background-color: #ffffff;  
  border: 1px solid rgba(0, 0, 0, 0.3);
  border-radius: 6px;
  box-shadow: 0 3px 7px rgba(0, 0, 0, 0.3);
  background-clip: padding-box;
}
.overlay-close {
  cursor: pointer;
  position: absolute;
  top: 10px;
  right: 10px;
  min-width: 40px;
  text-align: center;  
  border: 0;
  background: rgba(255, 255, 255, 0.8);
  color: black;  
  font-weight: 500;
  font-size: 18px;
  line-height: 12px;
  padding: 12px 15px;  
  border: 1px solid #e5e5e5;
  border-radius: 5px;
}
button.overlay-close:hover {
  border: 1px solid #b2b2b2;
}
.overlay-backdrop {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 900;
  background-color: #000000;
  opacity: 0.8;
  -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=80)";
}