/**
 * Detects the Content-Type header value for a given file extension or filename.
 *
 * Returns a full Content-Type value including charset when appropriate, based on
 * the charset defined in mime-db for the detected MIME type.
 *
 * @param extension The file extension (e.g. "css", ".css") or filename (e.g. "style.css")
 * @returns The Content-Type value, or undefined if not found
 *
 * @example
 * detectContentType('css')           // 'text/css;charset=utf-8'
 * detectContentType('.css')          // 'text/css;charset=utf-8'
 * detectContentType('style.css')     // 'text/css;charset=utf-8'
 * detectContentType('image.png')     // 'image/png'
 * detectContentType('unknown')       // undefined
 */
export declare function detectContentType(extension: string): string | undefined;
//# sourceMappingURL=detect-content-type.d.ts.map