@media screen and (max-width: 768px) {  
  html {
    font-size: 26.6666666666666667vw;
  }
  body {
    font-size: 16px;
  }
  .header .logo {
    color: #256BF7;
    margin-left: 4.267vw;
    margin-top: 8.27vw;
    width: 29.33vw;
  }

  .header .slogan {
    padding-left: 4.267vw;
    margin-bottom: 4.267vw;
    font-size: 11.2vw;
  }
 

  .header .publicity {
    position: relative;
    margin-left: 4.267vw;
    margin-right: 4.267vw;
    margin-bottom: 10.133vw;
  }

  .header .publicity_video_playButton {
    left: 4.267vw;
    bottom: 4.267vw;
    width: 12.267vw;
    height: 12.267vw;
    cursor: pointer;
  }

  .header .publicity_video_playButton:hover {
    background-color: #eee;
  }

  .header .download {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    z-index: 10;
    padding: 3.2vw 0;
    text-align: center;
    padding-bottom: calc(5vw + constant(safe-area-inset-bottom));
    padding-bottom: calc(5vw + env(safe-area-inset-bottom));
    justify-content: center;
    background-color: #fff;
  }

  .header .download_ios, .download_google  {
    display: inline-block;
    width: 43.73vw;
    height: 16vw;
  }

  .header .download_google {
    margin-left: 4vw;
  }
}



/* common 小屏幕 */

@media screen and (max-width: 768px) {

  .main {
    margin-bottom: 60px;
  }

  .main .title  {
    margin: 6.4vw 4.8vw 5.87vw 4.8vw;
    font-size: 9.07vw;
    font-weight: 900;
  }
  .main .main_case {
    margin: 0 6.93vw 0 6.93vw;
  }

  .main .main_case_item {
    padding: 0 !important;
  }

  .main .main_case_item_img {
    width: 11.733vw;
    height: 11.733vw;
  }

  .main .main_case_item_scene {
    margin-left: 3.47vw;
    margin-bottom: 6.67vw;
  }

  .main .main_case_item_scene h3 {
    margin: 2.67vw 0 2.13vw 0;
    font-size: 4.8vw;
  }

  .main .main_case_item_scene h4 {
    /* font-family: 'at-alipuhui-regular'; */
    font-size: 3.47vw;
    line-height: 4.8vw;
  }



  /* footer */
  .contact {
    position: fixed;
    bottom: 25.733vw;
    right: 4.267vw;
    user-select: none;
    z-index: 3;
  }

  .contact .twitter {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 14.4vw;
    height: 14.4vw;
    font-family: 'at-alipuhui-regular';
    line-height: 14.4vw;
    border-radius: 14.4vw;
    font-size: 8vw;
    user-select: none;
    color: #fff;
    text-align: center;
    text-decoration:none;
    background-color: #256BF7;
  }

  .contact .twitter img {
    width: 5.86vw;
  }

  .contact .contact_text {
    display: none;
  }


  .contact .twitter:active {
    background-color: #478ef9;
  }

  .footer {
    font-size: 3.2vw;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'at-alipuhui-regular';
    text-align: center;
    line-height: 5.33vw;
    color: #999999;
    margin-bottom: 33.6vw;
  }

  .footer a, .footer a:link, .footer a:active, .footer a:visited {
    color: #999999;
    text-decoration: none;
  }

  .footer-main {
    padding: 4.267vw 0 6.4vw 0;
    border-top: 1px solid #F2F2F2;
    width: 88vw;
    margin: 0 auto;
  }

}

/* common 大屏幕 */
@media screen and (min-width: 768px) {
  .main {
    margin-bottom: 173px;
  }

  .main .title  {
    margin: 52px 0;
    font-size: 48px;
  }
  .main .main_case {
    margin-left: -15px;
  }

  .main .main_case_item {
    margin-bottom: 52px;
    padding-right: 0;
  }

  .main .main_case_item_img {
    width: 52px;
    height: 52px;
  }

  .main .main_case_item_scene {
    margin-left: 12px;
    /* margin-bottom: 6.67vw; */
  }

  .main .main_case_item_scene h3 {
    margin: 18px 0 10px 0;
    font-size: 24px;
  }

  .main .main_case_item_scene h4 {
    font-size: 16px;
  }


  /* footer */
  .contact {
    position: fixed;
    bottom: 107px;
    left: 50%;
    transform: translate(-50%, 0);
    user-select: none;
    z-index: 3;
  }

  .contact .twitter {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 339px;
    background-color: #fff;
    height: 68px;
    line-height: 68px;
    font-family: 'at-alipuhui-regular';
    line-height: 68px;
    border-radius: 54px;
    font-size: 18px;
    user-select: none;
    color: #fff;
    text-align: center;
    text-decoration:none;
    background-color: #256BF7;
  }
  .contact .twitter img {
    margin-right: 6px;
    width: 22px;
  }


  .contact .twitter:hover {
    background-color: #478ef9;
  }

  .footer {
    
    color: #666666;
    font-size: 16px;
    
  
    
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'at-alipuhui-regular';
    text-align: center;
  }

  .footer a, .footer a:link, .footer a:hover, .footer a:visited {
    color: #666666;
    text-decoration: none;
  }

  .footer-main {
    border-top: 1px solid #F2F2F2;
    padding: 25px 25px;
    max-width: 1200px;
    margin: 0 auto;
  }

}