interface StyleProps {
    [key: string]: string | number;
}
/**
 * Add CSS rules to a stylesheet with a given title.
 * If a stylesheet with that title does not exist, it will be created.
 * @param selector The CSS selector to which to apply the rules.
 * @param cssRules An object containing CSS rules to apply.
 * @param title The title of the stylesheet.
 *
 * @example
 * addCss('.my-class', { color: 'red', backgroundColor: 'blue' }, 'my-stylesheet')
 * console.log(document.querySelectorAll('style').length > 0)
 *
 * @since 1.0.0
 */
declare function addCss(selector: string, cssRules: StyleProps, title?: string): void;
export default addCss;