html,
body,
header,
#Accueil {
    height: 100%;
}

#Accueil {
    background: url("/img/accueil.jpg")no-repeat center center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

.top-nav-collapse {
    background-color: #24355C;
}