html {
  display: table;
  table-layout: fixed;
  width: 100%;
  height: 100%;
}
#avertissement > p {
  font-size: 3rem;
  text-align: center;
}
#avertissement {
  display: none;
}
@media only screen and (orientation:portrait) {
  #wrapper {
    display: none;
  }
  #avertissement {
    display: block;
  }
}
@media only screen and (orientation:landscape) {
  #avertissement {
    display: none;
  }
}