.visual_area {
    background: url(../img/about_visual.jpg) no-repeat center;
    background-size: cover;
    margin-bottom: 75px;
}
.mar {
    margin-bottom: 60px !important;
}
.about h3 {
    text-align: center;
    font-family: 'Lato', sans-serif;
    font-weight: 300;
    position: relative;
    font-size: 1.25em;
}
.about h3 img {
    position: absolute;
    left: 50%;
    margin-left: -140px;
    top: -10px;
}
.about .sub_tit {
    text-align: center;
    font-size: 2.5em;
    font-weight: 300;
}
.about .sub_con {
    text-align: center;
    font-size: 1.125em;
    font-weight: 300;
    color: #555;
    line-height: 2em;
}
.about .sign {
    display: block;
    margin: 0 auto;
}
.img_box2 {
    padding-top: 60px;
    border-top: 1px solid #ddd;
    margin-bottom: 30px
}
.img_box2 img{
    width:100%;
}
.img_box3 img{
    width:100%;
}
.img_box {
    display: flex;
    justify-content: space-between;
}
.img_box div:first-of-type {
    width: 1140px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.img_box div:last-of-type {
    width: 570px;
}
.img_box img {
    width: 100%;
}
@media screen and (max-width:1280px) {
    .img_box div:first-of-type {
        width: 65%;
    }
    .img_box div:last-of-type {
        width: 32%;
    }
}
@media screen and (max-width:768px) {
    .img_box {
        flex-wrap: wrap;
    }
    .img_box div:first-of-type {
        width: 100%;
    }
    .img_box div:first-of-type img {
        margin-bottom: 20px;
    }
    .img_box div:last-of-type {
        width: 100%;
    }
}
@media screen and (max-width:640px) {
    .mar {
        margin-bottom: 30px !important;
    }
    .about h3 img {
        margin-left: -130px;
    }
    .about .sub_con {
        font-size: 1em;
    }
    .about .sub_con .m_none {
        display: none;
    }
}