I'm designing a significantly harder challenge that combines multiple complex patterns requiring advanced regex techniques. This challenge includes:
1. IPv6 addresses in different formats (standard, compressed, and mixed)
2. Credit card numbers with and without separators (only certain ones should match)
3. Complex URLs with query parameters
4. Similar-looking product codes where only specific patterns are valid
5. Hex color codes with tricky variations
6. Timestamps in different formats

This w... (truncated)