@media screen and (min-width: 630px) {
    .main_logo{
        display: block;
    }
    .main_logo_mini{
        display: none;
    }
}
@media screen and (max-width: 631px) {
    .main_logo{
        display: none;
    }
    .main_logo_mini{
        display: block;
    }
}