/**
 * thanks to Pimp Trizkit (function for darken color)
 * @param color: color you want to shadow, hex form
 * @param percent: percentage you want to shadow, in range [-100, 100]
 * @see https://stackoverflow.com/questions/5560248/programmatically-lighten-or-darken-a-hex-color-or-rgb-and-blend-colors
 */
export declare function shadeColor(color: string, percent: number): string;
export declare function addAlpha(color: string, alpha: number): string;