@mixin breakpoint($min: 0, $max: 0) {
  $type: type-of($min);

  @if $type == string
  {
    @if $min == sm
    {
      @media (max-width: $sm) { @content; }
    }
    @else if $min == md
    {
      @media (min-width: $sm) and (max-width: $md) { @content; }
    }
    @else if $min == lg
    {
      @media (min-width: $lg) { @content; }
    }
  }
  @else if $type == number
  {
    $query: "all" !default;
    @if $min != 0 and $max != 0 { $query: "(min-width: #{$min}) and (max-width: #{$max})"; }
    @else if $min != 0 and $max == 0 { $query: "(min-width: #{$min})"; }
    @else if $min == 0 and $max != 0 { $query: "(max-width: #{$max})"; }
    @media #{$query} { @content; }
  }
}