body {
  vertical-align: middle;
  background-image: url(img/eboy01.gif);
  background-repeat: no-repeat;
  background-size: 3200px 3200px;
}

h1 {
  text-align: center;
  font-weight: bold;
  color: floralwhite;
  font-size: 90px;
  font-family: bungee shade;
  margin-top: 10px;
}

.startbutton {
  animation: bounce 0.35s ease infinite alternate;
  margin-bottom: 190px;
}

@keyframes bounce {
  from {
    transform: translateY(0);
  }
  to {
    transform: translateY(-20px);
  }
}



.flex {
  /* style basique */
  width: 1200px;
  height: 1200px;
  border: 15px solid white;
  border-radius: 25px;

  /* instaure la flexbox */
  display: flex;
  align-items: center;
  justify-content: center;
  margin-left: auto;
  margin-right: auto;
  margin-top: 20px;
  background-image: url(img/rules.jpg);
  background-repeat: no-repeat;
  background-size: 1200px 1200px;
}