@function if-dark($if, $else: null) {
    @if $dark == 1 {
        @return $if;
    }
    @else {
        @return $else;
    }
}

@function if-light($if, $else: null) {
    @return if-dark($else, $if);
}

@mixin if-dark {
    @if $dark == 1 {
        @content;
    }
}

@mixin if-light {
    @if $dark != 1 {
        @content;
    }
}