@media only screen and (max-width:39.9em){
    div#box {
        width: calc(100% - 1.2em);
        margin-bottom:0!important;     
    }
   
}
@media only screen and (max-width:62em) and (min-width:40em) {
    div#box {width: 50%;margin-top: 1em;}

}