#sud_container > header {
    z-index: 9;
    position: fixed;
  /*  max-width: var(--largeur-ecran);*/
    width: 100%;
    top: 0;
    left: 0;
}

@media only screen and (min-width: 780px) {

}
@media only screen and (min-width: 1024px) {

}