I'm creating an extremely challenging regex puzzle that mixes multiple advanced formats in one text: emails, phone numbers with optional components and spaces, dates with different formats (ISO and European), and serial numbers containing alphanumeric groups separated by hyphens. This requires complex alternations, lookahead/lookbehind, and precise escaping to match only the intended patterns while ignoring similar but invalid items. The target items include correctly formatted emails, a phone n... (truncated)