media

In Sass, the @media directive may be nested and contain expressions.
$v: 1.5;
.sidebar {
   width: 300px;
   @media screen {
      width: 500px;
      @media  (orientation: landscape) and (-webkit-min-device-pixel-ratio: round($v + 0.2)) {
         height: 200px;
      } 
   }
}

.sidebar { width: 300px; } @media screen { .sidebar { width: 500px; } } @media screen and (orientation: landscape) and (-webkit-min-device-pixel-ratio: 2) { .sidebar { height: 200px; } }