body {
      
      margin:0% 0% 0% 0%;
      width: 100%;
background: url(../img/bg-latas.jpg) no-repeat #000;
-webkit-background-size: contain;
-moz-background-size: contain;
-o-background-size: contain;
background-size: cover;    }
      
.principal {
margin: 0 auto;
width: 100%;

        }
        
        
img {
height: auto;
max-width: 100%;

}

              
.logo {
margin: 5% auto;
width: 20%;

        }	
        
.boton {
margin: -5% auto;
width: 10%;

        }