/**
 * Shadow & Elevation System
 *
 * Shadows indicate elevation and hierarchy.
 * Subtle by default—prominence through restraint.
 *
 * "Good design is unobtrusive" - Dieter Rams
 *
 * @see /STANDARDS.md - Section 1.5 Elevation
 */
export declare const shadows: {
    readonly none: "none";
    readonly sm: "0 1px 2px 0 rgba(0, 0, 0, 0.5)";
    readonly md: "0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.5)";
    readonly lg: "0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -4px rgba(0, 0, 0, 0.5)";
    readonly xl: "0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.5)";
    readonly '2xl': "0 25px 50px -12px rgba(0, 0, 0, 0.75)";
    readonly 'glow-sm': "0 0 10px rgba(255, 255, 255, 0.05)";
    readonly 'glow-md': "0 0 20px rgba(255, 255, 255, 0.1)";
    readonly 'glow-lg': "0 0 40px rgba(255, 255, 255, 0.15)";
    readonly inner: "inset 0 2px 4px 0 rgba(0, 0, 0, 0.5)";
    readonly 'inner-lg': "inset 0 4px 8px 0 rgba(0, 0, 0, 0.5)";
};
export type ShadowKey = keyof typeof shadows;
/**
 * CSS custom property names for shadows
 */
export declare const shadowVars: {
    readonly '--shadow-none': "none";
    readonly '--shadow-sm': "0 1px 2px 0 rgba(0, 0, 0, 0.5)";
    readonly '--shadow-md': "0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.5)";
    readonly '--shadow-lg': "0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -4px rgba(0, 0, 0, 0.5)";
    readonly '--shadow-xl': "0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.5)";
    readonly '--shadow-2xl': "0 25px 50px -12px rgba(0, 0, 0, 0.75)";
    readonly '--shadow-glow-sm': "0 0 10px rgba(255, 255, 255, 0.05)";
    readonly '--shadow-glow-md': "0 0 20px rgba(255, 255, 255, 0.1)";
    readonly '--shadow-glow-lg': "0 0 40px rgba(255, 255, 255, 0.15)";
    readonly '--shadow-inner': "inset 0 2px 4px 0 rgba(0, 0, 0, 0.5)";
    readonly '--shadow-inner-lg': "inset 0 4px 8px 0 rgba(0, 0, 0, 0.5)";
};
/**
 * Generate CSS custom properties string
 */
export declare function generateShadowsCSS(): string;
/**
 * Get shadow by elevation level (semantic)
 */
export declare function getElevation(level: 'base' | 'raised' | 'elevated' | 'floating' | 'overlay'): string;