.grid {
  display: grid;
  grid-template-columns: auto;
  background-color: #2F4F4F;
  padding: 8px;
}

span.datestring{
  display:none;
}


.item {
   text-align: right;
}
.item:hover span.epoch{
  display:none;
}
.item:hover span.datestring{
  display:block;
}