@media only screen and (max-width: 900px) {
  .border-bottom {
    margin-bottom: 10px;
  }
  .border-bottom .about-dongri {
    margin-top: -35px !important;
  }
  .border-bottom .about-dongri .investor-relations {
    font-size: 15px!important;
  }
  .border-bottom .navigation #btn3 {
    width: 20% !important;
    margin: 0 2% !important;
    border-bottom: none !important;
  }
  .border-bottom .navigation #btn2 {
    width: 20% !important;
    margin: 0 2% !important;
  }
  .border-bottom .navigation #btn1 {
    width: 20% !important;
    margin: 0 2% !important;
    margin-right: 30% !important;
    border-bottom: 2px solid #bb0007;
  }
}