.full-screen {
    max-width: 100%;
    max-height: 100%;
    bottom: 0;
    left: 0;
    margin: auto;
    overflow: auto;
    position: fixed;
    right: 0;
    top: 0;
    -o-object-fit: contain;
    object-fit: contain;
}

#scrollBtn {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 30px;
  z-index: 99;
  font-size: 18px;
  outline: none;
  cursor: pointer;
  padding: 15px;
  font-weight: bolder;
}

#scrollBtn:hover {
  background-color: #555;