.grid-cmn{
    width: 100%;
    max-width: 540px;
    margin: 0 auto 20px;
}

@media all and (max-width:767px) {
    .grid-cmn{
        width: 100%;
        max-width: 400px;
        margin: 0 auto 20px;
    }
}

@media all and (min-width: 768px) {
    .grid-cmn>.col3 {
        width: 160px;
    }
}