.overlay {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background-color: RGBA(0, 0, 0, 0.75);
  z-index: 3;
  text-align: center; }

.overlay::before {
  content: "";
  height: 100%;
  width: 0px; }

.overlay .inset {
  width: 80%;
  max-width: 1000px;
  min-height: 250px;
  padding: 10px;
  background-color: #FFF; }

.overlay::before,
.overlay .inset {
  display: inline-block;
  vertical-align: middle; }