@function breakpoint-next($name, $breakpoint-names: map-keys($breakpoints)) {
  $n: index($breakpoint-names, $name);
  @return if($n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);
}

@function breakpoint-min($name) {
  $min: map-get($breakpoints, $name);
  @return if($min !=0, $min, null);
}

@function breakpoint-max($name) {
  $next: breakpoint-next($name);
  @return if($next, breakpoint-min($next) - 1px, null);
}

@function breakpoint-prefix($name) {
  @return if(breakpoint-min($name)==null, "", "-#{$name}");
}

@mixin breakpoint-up($name) {
  $min: breakpoint-min($name);
  @if $min {
    @media (min-width: $min) {
      @content;
    }
  }
  @else {
    @content;
  }
}

@mixin breakpoint-down($name) {
  $max: breakpoint-max($name);
  @if $max {
    @media (max-width: $max) {
      @content;
    }
  }
  @else {
    @content;
  }
}

@mixin media-breakpoint-between($lower, $upper) {
  $min: breakpoint-min($lower);
  $max: breakpoint-max($upper);
  @media (min-width: $min) and (max-width: $max) {
    @content;
  }
}

@mixin breakpoint-only($name) {
  $min: breakpoint-min($name);
  $max: breakpoint-max($name);
  @if $min !=null and $max !=null {
    @media (min-width: $min) and (max-width: $max) {
      @content;
    }
  }
  @else if $max==null {
    @include breakpoint-up($name);
  }
  @else if $min==null {
    @include breakpoint-down($name);
  }
}