html, body, svg { 
  width: 100%;
  height: 100%;
  font-family: 'Open Sans';
  margin: 0;
  display: block;
}
.landscape {
    visibility: hidden;
}
.square {
    visibility: initial;
}
@media (min-aspect-ratio: 4/5) and (min-height: 250px) {
    .landscape {
        visibility: initial;
    }
    .square {
        visibility: hidden;
    }
}
footer {
  background-color: rgba(15, 15, 15, 0.5);
  color: white;
  position: absolute;
  bottom: 2em;
  right: 1em;
  padding: .5em;
}
a { color: white; }