{"content":"I'm creating an extremely challenging regex problem that combines multiple pattern types with subtle valid/invalid distinctions. This challenge requires advanced techniques like lookaheads/lookbehinds, non-capturing groups, balanced delimiters, and precise boundary matching. The text contains multiple format categories including:\n\n1. Various datetime formats (ISO 8601, regional formats with different separators)\n2. Network addresses (IPv4/IPv6)\n3. Complex email addresses with special characters\n4. Product identifiers with specific formatting rules\n5. Multiple currency formats with different separators\n6. URLs with various components\n7. International phone numbers in different formats\n8. Credit card numbers with different separators\n9. Temperature readings with proper symbols\n10. Geographic coordinates with different notation styles\n11. Semantic versioning strings\n12. UUIDs/GUIDs\n13. Function definitions in different programming languages\n\nEach category inclu... (truncated)