@media (max-width:640px) {
  .banner {
    height: 43.75vw;
  }
  .ljjj {
    width: 100%;
    box-sizing: border-box;
    padding: 0 10px 20px 10px;
  }
  .ljjj .pic-wrapper {
    width: 100%!important;
    display: block!important;
  }
  .ljjj .pic-wrapper > .pic {
    width: 100%!important;
    height: auto!important;
  }
  .ljjj .section4 {
    display: block!important;
  }
  .ljjj .section4 .pic {
    width: 100%!important;
    height: auto!important;
  }
}