css nesting

@media only screen and (min-width: 1440px) {
    #menu_div {
        display: none;
    }
}

@media screen and (max-width: 1440px) {
    #menu_div {
        display: block;
        height: 30px;
        width: 30px;
        margin-right: 10px;
        margin-left: auto;
    }
}

@media only screen and (min-width: 1440px) {
    #menu_div {
        display: none;
    }
}

@media screen and (max-width: 1440px) {
    #menu_div {
        display: block;
        height: 30px;
        width: 30px;
        margin-right: 10px;
        margin-left: auto;
    }
}

#menu_div {
    @media screen and (max-width: 1440px) {
        display: block;
        height: 30px;
        width: 30px;
        margin-right: 10px;
        margin-left: auto;
    }
    @media screen and (min-width: 1440px) {
        display: none;
    }
}

#menu_div {
    @media screen and (max-width: 1440px) {
        display: block;
        height: 30px;
        width: 30px;
        margin-right: 10px;
        margin-left: auto;
    }
    @media screen and (min-width: 1440px) {
        display: none;
    }
}