desktop-first-css.css

 /* Set the background color of body to tan */
body {
  background-color: tan;
}

/* On screens that are 1200px or less, set the background color to red */
@media screen and (max-width: 1200px) {
  body {
    background-color: red;
  }
}

/* On screens that are 992px or less, set the background color to blue */
@media screen and (max-width: 992px) {
  body {
    background-color: blue;
  }
}

/* On screens that are 768px or less, set the background color to green */
@media screen and (max-width: 768px) {
  body {
    background-color: green;
  }
}

/* On screens that are 600px or less, set the background color to olive */
@media screen and (max-width: 600px) {
  body {
    background-color: olive;
  }
}