A mixin to add media query related style attributes

media_query.scss

@mixin breakpoint($point) {
  @if $point == large {
    @media (min-width: 1250px) { @content; }
  }
  @else if $point == medium {
    @media (min-width: 650px) { @content; }
  }
  @else if $point == small {
    @media (max-width: 650px)  { @content; }
  }
}

Usage:

.some-class {
   @include breakpoint(medium) {
      \\content
   }
}