//媒体查询
//下一个设备
@function device-next($name, $device: $media-min-width, $device-names: map-keys($device)) {
	$n: index($device-names, $name);
	@return if($n < length($device-names), nth($device-names, $n + 1), null);
}

//最小设备
@function device-min($name, $device: $media-min-width) {
    $min: map-get($device, $name);
    @return if($min != 0, $min, null);
}

//最大设备
@function device-max($name, $device: $media-min-width) {
	$next: device-next($name, $device);
	@return if($next, device-min($next, $device) - .02px, null);
}

//设备中缀
@function device-infix($name, $device: $media-min-width) {
    @return if(device-min($name, $device) == null, "", "-#{$name}");
}

//设备查询(大于等于)
@mixin media-min($name, $device: $media-min-width) {
    $min: device-min($name, $device);
    @if $min {
        @media (min-width: $min) {
            @content;
        }
    } @else {
        @content;
    }
}

//设备查询(小于等于)
@mixin media-max($name, $device: $media-min-width) {
    $max: device-max($name, $device);
    @if $max {
        @media (max-width: $max) {
            @content;
        }
    }
    @else {
        @content;
    }
}

//在..之间设备查询
@mixin media-between($lower, $upper, $device: $media-min-width) {
    $min: device-min($lower, $device);
    $max: device-max($upper, $device);
    @if $min != null and $max != null {
        @media (min-width: $min) and (max-width: $max) {
            @content;
        }
    }
    @else if $max == null {
        @include media-min($lower, $device) {
            @content;
        }
    }
    @else if $min == null {
        @include media-max($upper, $device) {
            @content;
        }
    }
}

//指定设备查询(唯一设备)
@mixin media-only($name, $device: $media-min-width) {
    $min: device-min($name, $device);
    $max: device-max($name, $device);
    @if $min != null and $max != null {
        @media (min-width: $min) and (max-width: $max) {
            @content;
        }
    }
    @else if $max == null {
        @include media-min($name, $device) {
            @content;
        }
    }
    @else if $min == null {
        @include media-max($name, $device) {
            @content;
        }
    }
}

//自定义设备查询
@mixin media-custom($min, $max: null, $reverse: false) {
    @if $min != null and $max != null {
        @if $reverse {
            @media (max-width: $max) and (min-width: $min) {
                @content;
            }
        }
        @else { 
            @media (min-width: $min) and (max-width: $max) {
                @content;
            }
        }
    }
    @else if $max == null {
        @media (min-width: $min) {
            @content;
        }
    }
    @else if $min == null {
        @media (max-width: $max) {
            @content;
        }
    }
}