@media only screen and (min-width: 320px) {
    #login-bg {
        height: 100%;
    }
}

@media only screen and (min-width: 481px) {
    #login-bg {
        height: auto;
    }
}

@media only screen and (min-width: 769px) {
    #login-bg {
        height: 100%;
    }
}

@media only screen and (min-width: 1025px) {
    #login-bg {
        height: 100%;
    }
}