/**
 * Helper function to check if an element has a specific computed style.
 * @param element - The DOM element to check
 * @param styleString - CSS style string in the format "property: value" (e.g., "opacity: 0", "z-index: 1001")
 * @returns true if the computed style matches, false otherwise
 */
export declare function hasComputedStyle(element: HTMLElement | null, styleString: string): boolean;
declare module "vitest" {
    interface Assertion {
        toHaveComputedStyle(styleString: string): void;
    }
    interface AsymmetricMatchersContaining {
        toHaveComputedStyle(styleString: string): void;
    }
}