@function contrast-color-by($base_color_var, $percent) {
    @return if(lightness($base_color_var) > 50, darken($base_color_var, $percent), lighten($base_color_var, $percent));
}
@function reverse-gradient-for($gradient) {
    @if $gradient == 'matte' {
        @return 'matte-reverse';
    }
    @else if $gradient == 'matte-reverse' {
        @return 'matte';
    }
    @else if $gradient == 'bevel' {
        @return 'recessed';
    }
    @else if $gradient == 'recessed' {
        @return 'bevel';
    }
    @else if $gradient == 'glossy' {
        @return 'glossy-reverse';
    }
    @else if $gradient == 'glossy-reverse' {
        @return 'glossy';
    }
    @else {
        @return $gradient;
    }
}