.banner {
  position: relative;
}
.banner img:nth-of-type(1) {
  width: 100%;
  z-index: 10;
}
.banner img:nth-of-type(2) {
  display: none;
}
.banner img:nth-of-type(3) {
  width: 50%;
  position: absolute;
  top: 40%;
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
}
@media (max-width: 768px) {
  .banner img {
    width: 100%;
  }
  .banner img:nth-of-type(1) {
    display: none;
  }
  .banner img:nth-of-type(2) {
    display: inline-block;
  }
  .banner img:nth-of-type(3) {
    width: 80%;
    position: absolute;
    top: 40%;
    left: 50%;
    transform: translateX(-50%);
    z-index: 100;
  }
}