gistfile1.scss

$tablet: "...";
$tablet-landscape: "...";
$desktop: "...";

body {
  // style for mobile (STYLE A)
  
  @media #{$tablet} {
    //style for tablet (STYLE B)
  }
  
  @media #{$tablet-landscape} {
    //style for tablet landscape (STYLE C)
  }
  
  @media #{$desktop} {
    //style for desktop (STYLE C)
  }
}

//since tablet-landscape and desktop share same style, is it possible to do this?

body {
  //style
  
  @media #{$tablet-landscape},
  @media #{$desktop} {
    //style for both tablet-landscape and desktop
  }
}