#intro {
  background-image: url(../img/sub/about/bg.jpg);
}
/* ----- content start ----- */
#content .imgs {
  width: 100%;
  overflow: hidden;
}

#content .imgs img {
  margin: auto;
  max-width: 100%;
}

#content .imgs .t_img,
#content .imgs .m_img {
  display: none;
}

@media screen and (max-width: 800px) {
  .w_img {
    display: none;
  }

  #content .imgs .t_img {
    display: block;
  }
}

@media screen and (max-width: 460px) {
  #content .imgs .t_img {
    display: none;
  }

  #content .imgs .m_img {
    display: block;
  }
}