@media (min-width: 120px) {
  .bg {
    position: relative;
    display: flex;
    align-items: center;
    width: 98vw;
    height: 100vh;
    background-color: #191919;
  }
  .bg .btn_box {
    position: absolute;
    top: 2rem;
    right: 0;
    font-size: 4rem;
    line-height: 8rem;
  }
  .bg .btn_box #back_btn,
  .bg .btn_box .second_count,
  .bg .btn_box .finished {
    margin: 1rem;
    width: 8rem;
    text-align: center;
    background-color: #191919;
    border: 0.1rem solid #fff;
    box-shadow: 0.5rem 0.5rem 0.8rem 0px #191919;
    border-radius: 0.5rem;
    color: #fff;
  }
  .bg .btn_box #back_btn a,
  .bg .btn_box .second_count a,
  .bg .btn_box .finished a {
    text-decoration: none;
    color: #fff;
  }
  .bg .ad_url {
    margin: 0 auto;
    width: 96rem;
    height: 54rem;
  }
  .bg .ad_url iframe {
    width: 100%;
    height: 100%;
  }
}
@media (min-width: 750.1px) {
  .bg {
    position: relative;
    display: flex;
    align-items: center;
    width: 98vw;
    height: 100vh;
    background-color: #191919;
  }
  .bg .btn_box {
    position: absolute;
    top: 1rem;
    right: 0;
    font-size: 1.5rem;
    line-height: 3rem;
  }
  .bg .btn_box #back_btn,
  .bg .btn_box .second_count,
  .bg .btn_box .finished {
    margin: 0.5rem;
    width: 4rem;
    text-align: center;
    background-color: #191919;
    border: 0.1rem solid #fff;
    box-shadow: 0.5rem 0.5rem 0.8rem 0px #191919;
    border-radius: 0.5rem;
    color: #fff;
  }
  .bg .btn_box #back_btn a,
  .bg .btn_box .second_count a,
  .bg .btn_box .finished a {
    text-decoration: none;
    color: #fff;
  }
  .bg .ad_url {
    margin: 0 auto;
    width: 64rem;
    height: 36rem;
  }
  .bg .ad_url iframe {
    width: 100%;
    height: 100%;
  }
}