body{
    margin: 0;
}

main{
    width: 80%;
    margin: auto;
}

.diapo{
    position: relative;
    overflow: hidden;
}

#nav-droite, #nav-gauche{
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    color: white;
    font-size: 3em;
}

#nav-droite{
    right: 20px;
}
#nav-gauche{
    left: 20px;
}

.elements{
    display: flex;
    transition: 1s linear;
}

.element{
    flex: 1 0 100%;
    position: relative;
}

.element > img{
    width: 40%;
}

.caption{
    position: relative;
    top: 90%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    background-color: rgba(255,255,255,0.4);
    padding: 30px;
}