@media screen and (max-width: 750px) {
  /* 第一屏 */
  .a-bg1 {
    height: 2.56rem;
  }
  .a1-title {
    padding: 1.12rem 0 .15rem;
    font-size: .36rem;
    height: auto;
  }
  .a1-sec-title {
    font-size: .28rem;
    height: auto;
  }
  /* 第二屏 */
  .a-bg2 {
    height: 5.18rem;
  }
  .common-title {
    font-size: .3rem;
    padding-top: .6rem;
    height: auto;
  }
  .common-tip {
    margin-top: .24rem;
    font-size: .26rem;
    line-height: .32rem;
    height: auto;
  }
  .a2-content {
    height: 3.39rem;
  }

  .a2-image1 {
    top: .48rem;
    left: .73rem;
    width: 1.21rem;
  }
  
  .a2-image2 {
    width: 1.23rem;
    top: .4rem;
    left: 3.3rem;
  }
  
  .a2-image3 {
    width: 1.58rem;
    top: .68rem;
    left: 5.38rem;
  }
  
  .a2-image4 {
    width: 1.62rem;
    top: 2.24rem;
    left: .1rem;
  }
  
  .a2-image5 {
    top: 2.14rem;
    left: 1.69rem;
    width: .91rem;
  }
  
  .a2-image6 {
    width: .96rem;
    top: 2.2rem;
    left: 4.03rem;
  }
  
  .a2-image7 {
    top: 2rem;
    left: 6.36rem;
    width: .75rem;
  }
  .a-bg3 {
    height: 5.3rem;
  }
  .a3-content {
    padding: .4rem .3rem 0;
  }
  .a3-content img:first-child {
    width: 3.06rem;
    height: 3.95rem;
  }
  .a3-title {
    padding-top: .32rem
  }
  .a3-last-image {
    width: 3.63rem;
    height: 4.04rem;
    margin-top: 0;
    display: none;
  }
  .a3-last-image1 {
    display: block;
  }
  /* 第四屏 */
  .a-bg4 {
    height: 6.9rem;
  }
  .a4-title {
    padding-top: .6rem;
  }
  .a4-content {
    padding-top: .47rem;
    flex-flow: row wrap;
  }
  .a4-item{
    width: 50%;
  }
  .a4-item:nth-child(-n + 2){
    margin-bottom: .65rem;
  }
  .a4-content img {
    width: 1.28rem;
    height: auto;
  }
  .a4-text {
    margin-top: .15rem;
    height: auto;
    font-size: .28rem;
    white-space: nowrap;
  }
}