.about_us {
    padding-top: 24px;
}

.about_us .intro_tit {
    width: 100%;
}

.about_txt {
    padding-top: 10px;
}

.about_txt p {
    line-height: 24px;
    font-size: 16px;
    color: #000;
    text-indent: 2em;
}
.ab_img{
    width: 75%;
    height: auto;
    margin: 100px auto 0;
}
.ab_img img{
    width: 100%;
    height: auto;
}
.friend_link{
    padding-top: 70px;
    padding-bottom: 22px;
}
@media screen and (max-width:767px){
    .ab_img{
        width: 100%;
        margin-top: 50px;
    }
    .friend_link{
        padding-top: 50px;
    }
}