实现移动端border-1px

 @media (-webkit-min-device-pixel-ratio: 1.5),
    (min-device-pixel-ratio: 1.5) {
      .border-1px::after {
        -webkit-transform: scaleY(0.7);
         transform: scaleY(0.7)
      }
    }
    @media (-webkit-min-device-pixel-ratio: 2),
    (min-device-pixel-ratio: 2) {
      .border-1px::after {
        -webkit-transform: scaleY(0.7);
        transform: scaleY(0.7)
      }
    }
    div{
      height: 220px;
      width: 100%;
      border:1px solid #ccc;
      display: flex;
      justify-content: center;
      align-items: center;
      font-size: 80px;
    }