@mixin breakpoint($point) {
    @if $point == small {
      @media only screen and (min-width: 600px) { @content; }
    }
    @else if $point == medium {
      @media only screen and (min-width: 768px) { @content; }
    }
    @else if $point == large {
      @media only screen and (min-width: 992px) { @content; }
    }
    @else if $point == x-large {
      @media only screen and (min-width: 1200px) { @content; }
    }
    @else {
      @error "Unknown breakpoint #{$point}.";
    }
  }