body{
    background-position: center;
    background-repeat: inherit;
    background-size: cover;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    height:100%;

}

.invalid { color: red !important; }


@media (min-width: 768px) {

  }

@media (min-width: 576px)
.col-sm-12{
    -ms-flex: 0 0 100%;
    flex: 0 0 100%;
    max-width: 100%;
    text-align: center;
}