.content {
  opacity: 0;
  display: block;
  transition: opacity .5s ease;
}

.chargement {
  z-index: 99;
  display: inline-block;
  width: 80px;
  height: 80px;
  display: block;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  opacity: 1;
  transition: opacity .2s ease;
}

.chargement:after {
  content: " ";
  display: block;
  width: 64px;
  height: 64px;
  margin: 8px;
  border-radius: 50%;
  border: 6px solid #fff;
  border-color: #fff transparent #fff transparent;
  animation: lds-dual-ring 1s linear infinite;
}

@keyframes lds-dual-ring {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(360deg);
  }
}