.viewer {
  //width: 100vw;
  //height: 100vh;
  background: url("cosmicmetropolis_web.gif");
  background-color: black;
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
  margin: 0 auto;
      box-shadow: grey 2px 2px 224px -28px;
}

.main-container {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  position: relative;
}

.row {
  position: relative;
  height: calc(100% / 3);
}

.main-container.highlight .viewer{
  opacity: 0;
}

.main-container.highlight .overlay {
  opacity: 1;

}

.row .panel {
  display: inline-block;
  width: calc(100% / 6);
  height: 100%;
  cursor: pointer;
  margin-right: -4px;
  opacity: 0;
  background: white;
  transition: .3s all;
}

.row .panel:hover {
  opacity: .5;
}

.overlay {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  opacity: 0;
  background-size: contain;
  background-position: center;
  z-index: -1;
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
}

body, html, .overlay {
    padding: 0px;
    margin: 0px;

}