body {
  margin: 0;
  font-family: Arial, sans-serif;
}
.banner {
  width: 100%;
  height: auto;
}
.desktop {
  display: block;
}
.mobile {
  display: none;
}
@media only screen and (max-width: 768px) {
  .desktop {
    display: none;
  }
  .mobile {
    display: block;
  }
}