body { 
  margin:0;
  padding:0;
  background: url(../img/exemples/fond_site.jpg) no-repeat center fixed; 
  -webkit-background-size: cover; /* pour anciens Chrome et Safari */
  background-size: cover; /* version standardisée */
}

h1 {font-size: 3em;}
h2 {font-size: 1.9em;}
h6 {font-size: 1.3em;}
.menu > li > a {font-size: 1.4em;}
.recherche > li > a {font-size: 1.4em;}