.is-style-rose-gauche {
    background-image: url(../img/vector-2.png);
    background-repeat: no-repeat;
    background-position: left;
}

.is-style-rose-droite {
    background-image: url(../img/vector-1.png);
    background-repeat: no-repeat;
    background-position:top right;
}

@media screen and (max-width: 768px) { 
    .is-style-rose-gauche , .is-style-rose-droite {
        background-position: top;    
    }
}