.invisible {
  display: none;
}

.modal {
  background: #f0f0f0;
  /* Fallback */
  background: rgba(255, 255, 255, 0.6);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 10;
}
.modal div {
  max-width: 96rem;
  text-align: center;
  margin: 10% auto;
  width: 80%;
}
.modal div .stand-row {
  margin: 2em 0;
  width: 100%;
}
.modal div .stand-column {
  width: 33%;
  display: inline;
}
.modal div .stand-column a img {
  width: 20%;
  max-width: 100px;
  margin: 0 auto;
  -webkit-filter: grayscale(50%);
          filter: grayscale(50%);
  border: 0;
}