.diaporama{
  width:100%;
  height: 0px;
  padding-top: 34.74%;
  background-color: #EDEDED;
  background-size: contain;
  animation: fondu 15s step-end infinite both;
}
@keyframes fondu{
    0%{background-image: url("Images/cave/cave2-min.jpg");}
    33.33%{background-image: url("Images/cave/cave1-min.jpg");}
    66.66%{background-image: url("Images/cave/cave3-min.jpg");}
    100%{background-image: url("Images/cave/cave2-min.jpg");}
}

.logo_demarches{
  padding:2%;
  width: 100px;
}