@media not screen and (max-width: 50rem) {

    .txtTit1 {
        font-size: 40px;
    }

    .txtTit2 {
        font-size: 22px;
    }

    .txtTit3 {
        font-size: 26px;
    }

    .txtTxt {
        font-size: 22px;
    }

    .txtTxt2 {
        font-size: 18px;
    }

    .imgMainL {
        visibility: visible;
        height: 100%;
    }

    .imgMainS {
        visibility: hidden;
        display: none;
        height: 0px;
    }
}

@media only screen and (max-width: 50rem) {
    .txtTit1 {
        font-size: 26px;
    }

    .txtTit2 {
        font-size: 16px;
    }

    .txtTit3 {
        font-size: 18px;
    }

    .txtTxt {
        font-size: 16px;
    }

    .txtTxt2 {
        font-size: 16px;
    }

    .imgMainL {
        display: none;
        visibility: hidden;
        height: 0px;
    }

    .imgMainS {
        visibility: visible;
        height: 100%;
    }
}