body {
  background-color: black;
  background-image: url('../images/bk.jpg');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center center;
}

body.jaune {
  background-color: #FFFF80;
}
body.vert {
  background-color: #91EEA0;
}
body.jaune a {
  color: #FFFFFF;
}
body.jaune #s_s {
  color: #000000;
}
body.vert #s_s {
  color: #FF8000;
}