html { 
  margin:0;
  padding:0;
  background: url(../img/fond-chave.jpg) no-repeat center fixed; 
  -webkit-background-size: cover; /* pour Chrome et Safari */
  -moz-background-size: cover; /* pour Firefox */
  -o-background-size: cover; /* pour Opera */
  background-size: cover; /* version standardisée */
}

body{
  margin:0;
  padding:0;
}

.content-1 {
  max-width:990px;
  margin: 120px auto 0 auto;
  text-align:center;
}

.content-2 {
  position:fixed;
  bottom:100px;
  height:60px;
  width:100%;
  text-align:center;
}

.bas {
  position:fixed;
  bottom:0;
  height:60px;
  background-color:#000;
  margin:0;
  padding:0;
  width:100%;
  text-align:center;
}

@media screen and (max-width: 1600px) {
  .content-1 {
    margin: 40px auto 0 auto;
  }  
}

@media screen and (max-width: 1200px) {
  .content-1 {
    margin: 20px auto 0 auto;
  }  
}