/**
 * Lightweight HTML formatter that indents well-formed HTML markup.
 * Replaces js-beautify for the snapshot-markup use case where
 * input is always valid DOM serialization (outerHTML).
 */
export interface HtmlFormatOptions {
    /** Number of spaces per indent level (default: 4) */
    indent_size?: number;
}
/**
 * Format an HTML string with proper indentation.
 *
 * @param html - The HTML string to format (must be well-formed)
 * @param options - Formatting options
 * @returns The formatted HTML string
 */
export declare function formatHtml(html: string, options?: HtmlFormatOptions): string;