body{
    background-image:url(phare.jpg);
    background-size:cover;
}
main{
    padding:4em;
}

main article {
    display:flex;
    background-color:rgba(255, 255, 255, 0.7);
    padding:2em;
    justify-content:space-between;
}
main .col {
    width:48%;
}
main .col .image-responsive {
    width:100%;
    height:auto;
}