.about-publicNotice{
    background-image: url(../img/public_notice-mainimage.jpg);
    background-repeat: no-repeat;
    background-position: top center;
    position: relative;
}

.about-publicNotice::after{
    position: absolute;
    bottom: 0;
    right: 0;
    font-size: 0;
    content: url(../img/mainimage-after.png);
}
main{
    margin-bottom: 100px;
}