@media screen and (min-width: 480px) and  (max-width: 767px) {
  body {
    background-color: black;
    color: white;
  }
}
@media screen and (min-width: 768px) {
  body {
    background-color: yellowgreen;
  }
  .column {
    width: 220px;
    float: left;
    padding: 15px;
  }
}