body {
    background-repeat:no-repeat !important;
    background-position:top center !important;
    background-attachment:fixed !important;
    background-image:url('fond.jpg') !important;
    }
    @media (max-width:800px) {
     body {
     background-image: none !important;
     }
    }
    
     #contenu_logo{
    background-image:url('haut.jpg') !important;
    }
    @media (max-width:800px) {
     #contenu_logo {
     background-image: none !important;
     }
    }
    
     #contenu_logo_gauche{
    content:url('logo_gauche.png') !important;
    }
    
     #contenu_logo_droite{
    content:url('logo_droit.png') !important;
    }