@media screen and (min-width: 768px) {
    .join-mt {
        margin-top: -300px;
    }
    .join-mb-bg {
        background: url(//qn1.10soo.net/assets23/202312191439594.svg) no-repeat;
        background-size: cover;
        background-position: center 20%;
    }
}
@media screen and (min-width: 1400px) {
    .join-mt {
        margin-top: -300px;
    }
    .join-mb-bg {
        background: url(//qn1.10soo.net/assets23/202312191439594.svg) no-repeat;
        background-size: cover;
        background-position: center 30%;
    }
}