/**
 * Return all custom variables from the document.
 * Derived from: stackoverflow.com/questions/45763121/list-css-custom-properties-css-variables
 *
 * @example
 * const allCustomCSSVariables = getCustomCSSVariables('<p>example</p>')
 *
 * @returns {Array<{key: string, value: string}>} Array of CSS variable objects with key and value properties
 */
export declare function getCustomCSSVariables(): Array<{
    key: string;
    value: string;
}>;