#casa {
  height: 100vh;
  width: 100%;
  margin: 0;
  border: 0;
  padding: 0;
  cursor: pointer;
  display: none;
  position: relative;
  animation: fadein 3s;
}
#pnb {
  width: 100%;
  height: 100%;
  position: relative;
}
#pnb img {
  width: 80%;
  height: 80%;
  position: absolute;
  -webkit-transition: opacity 1s ease-in-out;
  -moz-transition: opacity 1s ease-in-out;
  -o-transition: opacity 1s ease-in-out;
  transition: opacity 1s ease-in-out;
  top: 10%;
  left: 10%;
}
#pnb img.cima:hover {
  opacity: 0;
}
@keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}