/**
 * Decreases the opacity of a color. Its range for the amount is between 0 to 1.
 *
 * @example
 * background: transparentize(0.1, '#fff');
 * background: transparentize(0.2, 'hsl(0, 0%, 100%)'),
 * background: transparentize(0.5, 'rgba(255, 0, 0, 0.8)'),
 */
export declare function transparentize(amount: number, color: string): string;