body {
    background: #57dbe8 url(../images/bg.jpg) no-repeat 50% 50% fixed; 
-moz-background-size: 100%; /* Firefox 3.6+ */ 
-webkit-background-size: 100%; /* Safari 3.1+ и Chrome 4.0+ */ 
-o-background-size: 100%; /* Opera 9.6+ */ 
background-size: 100%; /* Современные браузеры */ 
}