.sectionPresentation {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: horizontal;
    -webkit-box-direction: normal;
    -ms-flex-direction: row;
    flex-direction: row;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    overflow: visible;
    padding: 80px 0;
    position: relative;
    width: 100%;
    margin: 0 auto;
    border:0px solid green;
}

.sectionPresentation h3{
    font-weight: bold;
    margin-bottom: 0px;
}

.imagePresentation {
    -webkit-box-flex: 1;
    -ms-flex: 1 1 40%;
    flex: 1 1 40%;
    position: relative;
    -webkit-animation: slideInLeft 1s ease forwards;
    animation: slideInLeft 1s ease forwards;
    opacity: 0;
}

.img-desktop {
    display: block;
}

.img-mobile {
    display: none;
}

.imagePresentation img {
    position: absolute;
    top: -260px; /* décalage sous la section */
    left: 0;
    width: 100%;
    max-width: 500px;
    height: auto;
}

.contentPresentation {
    -webkit-box-flex: 1;
    -ms-flex: 1 1 60%;
    flex: 1 1 60%;
    padding: 0px;
    padding-left: 100px;
    -webkit-animation: slideInLeft 1s ease forwards;
    animation: slideInLeft 1s ease forwards;
    opacity: 0;
}

@media (max-width: 1400px) {
    .sectionPresentation {
        width: auto;
    }
    .imagePresentation img {
        top: -260px; /* décalage sous la section */
    }
    .sectionPresentation h3{
        font-size: 3em;
    }
}

@media (max-width: 1250px) {
    .imagePresentation img {
        top: -220px; /* décalage sous la section */
        width: 480px;
    }
}

@media (max-width: 1100px) {
    .sectionPresentation {
        -webkit-box-orient: vertical;
        -webkit-box-direction: reverse;
        -ms-flex-direction: column-reverse;
        flex-direction: column-reverse;
        padding: 40px 0px;
        text-align: left;
        width: auto;
        margin-bottom: 200px;
    }

    .imagePresentation {
        -webkit-animation: slideInLeft 1s ease forwards;
        animation: slideInLeft 1s ease forwards;
        margin-bottom: 20px;
    }

    .imagePresentation img {
        position: static;
        margin-bottom: 0;
        margin-top: 2em;
        width: auto;
        max-width: 500px;
    }

    .img-desktop {
        display: none;
    }

    .img-mobile {
        display: block;
        width: 100%;
        height: 200px;
        -o-object-fit: cover;
        object-fit: cover;
        -o-object-position: center top;
        object-position: center top;
    }

    .contentPresentation {
        -webkit-animation: slideInLeft 1s ease forwards;
        animation: slideInLeft 1s ease forwards;
        padding: 0 20px;
    }
}

@media (max-width: 500px) {
    
    .sectionPresentation h3{
        font-size: 2.75em;
    }
    .sectionPresentation {
        margin-bottom: 50px;
    }
    .imagePresentation img {
        max-width: 350px;
    }
}

@media (max-width: 450px) {
    .sectionPresentation h3{
        font-size: 2.2em;
    }
}

@media (max-width: 420px) {
    .sectionPresentation h3{
        font-size: 2em;
    }
}

/***************** Animations ***************/

@-webkit-keyframes slideInLeft {
    0% {
        -webkit-transform: translateX(-30px);
                transform: translateX(-30px);
        opacity: 0;
    }
    100% {
        -webkit-transform: translateX(0);
                transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideInLeft {
    0% {
        -webkit-transform: translateX(-30px);
                transform: translateX(-30px);
        opacity: 0;
    }
    100% {
        -webkit-transform: translateX(0);
                transform: translateX(0);
        opacity: 1;
    }
}
/*********************************************/