.conteneur{
    width: 100%;
    height: 600px;
    margin-bottom: 50px;
}

.d3[target="Tesson"]{
    width:100%;
    height:700px;
    box-shadow: 0px 0px 10px #777;
    background-color: #EDEDED;
    background-size: contain;
    animation: Fondu 20s  infinite both;
}

@keyframes Fondu {
    0%{background-image: url("imagescss/TessonsV1.JPG"); background-size: contain; background-repeat: no-repeat;background-position: center;}
    100%{background-image: url("imagescss/TessonsV2.png"); background-size: contain; background-repeat: no-repeat;background-position: center;}
}