div#haut ul h2 {
    display: block;
    text-align: center;
}

div#bas {
    margin-left: 3%;
    margin-right: 3%;
    text-align: center;
}

#bas ul li{
    display: block;
}

#bas ul a .img {
    height: 400px;
    display: block;
    margin: auto;
}