.overlay {
  height: 0%;
  width: 100%;
  position: fixed;
  z-index: 1000;
  bottom: 0;
  left: 0;
  background-color: black;
  background-color: rgba(0, 0, 0, 0.95);
  overflow-y: hidden;
  transition: 0.5s; }
  .overlay a {
    padding: 8px;
    text-decoration: none;
    font-size: 36px;
    color: #818181;
    display: block;
    transition: 0.3s;
    color: #DDD; }
  .overlay a:hover, .overlay a:focus {
    /*color: #f1f1f1;*/
    color: #f00; }
  .overlay .closebtn {
    position: absolute;
    /*top: 20px;
       right: 45px;*/
    top: -20px;
    right: 0;
    font-size: 60px;
    z-index: 2000;
    /*SD Add*/ }
  .overlay-content {
    position: relative;
    top: 0;
    width: 100%;
    text-align: center;
    /*margin-top: 30px;*/
    padding: 15px;
    /*SD Add*/
    height: 100%;
    /*SD Add*/
    /*display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;*/ }

@media screen and (max-height: 450px) {
  .overlay {
    overflow-y: auto; }
  .overlay a {
    font-size: 20px; }
  .overlay .closebtn {
    font-size: 40px;
    top: 1vh;
    right: 1vw; } }

@media screen and (max-width: 543px) {
  .overlay {
    overflow-y: auto; }
  .overlay a {
    font-size: 20px; }
  .overlay .closebtn {
    font-size: 40px;
    top: -15px;
    right: 5px; } }