:root {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
:root #pcImg {
  width: 100%;
}
:root #pcImg img {
  width: 100%;
  display: block;
}
:root #mobileImg {
  width: 100%;
  display: none;
}
:root #mobileImg img {
  width: 100%;
  display: block;
}
@media screen and (max-width: 425px) {
  :root #pcImg {
    display: none;
  }
  :root #mobileImg {
    display: block;
  }
}