.box {
  height: 10rem;
  width: 10rem;
  background-color: red;
  border-radius: 0.5rem;
}

/* this will make box red color if the device width is greater than 768px */
@media (min-width: 768px) {
  .box {
    background-color: blue;
  }
}

/* this will make box red color if the device width is greater than 1024px */
@media (min-width: 1024px) {
  .box {
    background-color: yellow;
  }
}