html {
scroll-behavior: smooth ;    
}
h2,h3,h4, .nav.item,#transition, footer{
    text-align:center
}
/* ******* HEADER ******** */
header{
    background: url(./media/main3.jpeg)no-repeat 50% 50%;
    background-size: cover;
    height: 40vh;
    border-radius: 0px 0px 20px 20px ;
    margin-bottom: 40px;
}
h1{
    font-size  5em;
    padding: 50px 0 0 10%;
    text-shadow: -3px 3px 2px #ffffff;
    animation: titre ease 1.5s;
}
@keyframes titre{
    0%{
        opacity: 0;
        transform: translate(60px,75px)
    }
    100%{
        opacity: 1;
        transform: translate(0px,0px);
    }