Some example media queries.

media_queries.css

@media screen {
      body {
          width: 75%;
      }
}

@media print {
      body {
          width: 100%;
      }
}
@media all and (max-width: 699px) and (min-width: 520px), (min-width: 1151px) {
  body {
    background: #ccc;
  }
}