export interface RGB {
    r: number;
    g: number;
    b: number;
    a?: number;
}
export declare function parseColor(color: string): RGB | null;
export declare function flattenColor(foreground: RGB, background: RGB): RGB;
export declare function getRelativeLuminance(color: RGB): number;
export declare function getContrastRatio(foreground: RGB, background: RGB): number;
export declare function getEffectiveBackgroundColor(element: Element): RGB;
export declare function isLargeText(element: Element): boolean;
export declare function formatColor(color: RGB): string;