#closed_cover {
  background: rgba(0,0,0,0.5);
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
}
#closed_cover_strings {
  display:table-cell;
  vertical-align: middle;
  text-align: center;
  color: #fff;
  font-size: xx-large;
  font-weight: bolder;
}