.pc1{
  background: url('../image/technology/pc1.jpg') center no-repeat;
  background-size: 100% 100%;
}
.mob1,.mob2,.mob3,.mob4,.mob5{
  display: none;
}
@media screen and (min-width: 1600px){
}
@media screen and (max-width:768px) {
  .pc1,.pc2,.pc3,.pc4,.pc5{
      display: none;
  }
  .mob1,.mob2,.mob3,.mob4,.mob5{
      display: block;
  }
  .mob1{
      background: url('../image/technology/mob1.jpg') center no-repeat;
      background-size: 100% 100%;
  }
  .mob2{
    background: url('../image/technology/mob2.jpg') center no-repeat;
    background-size: 100% 100%;
  }
  .mob3{
    background: url('../image/technology/mob3.jpg') center no-repeat;
    background-size: 100% 100%;
  }
  .mob4{
    background: url('../image/technology/mob4.jpg') center no-repeat;
    background-size: 100% 100%;
  }
  .mob5{
    background: url('../image/technology/mob5.jpg') center no-repeat;
    background-size: 100% 100%;
  }
}