Nice design! And the final answer is much much simpler than I thought. (+_+)
Hint (encoded in base64/UTF-8 to avoid spoiler):
- XiBpcyB0aGUgaW5zZXJ0IChlLmcuLCB6ZXJvKSBzeW1ib2wu
- 4oCcYXh4eHjigJ0g4omhIOKAnGEweHh4eOKAnSAobW9kIDcpIOKHlCBhIOKJoSAxMCBhIChtb2QgNykg4oeUIGEgPSA3Lg==
- V2UgYXJlIG5vdCBhYmxlIHRvIGVudGVyIG1vcmUgdGhhbiAxMiA9IDkrMyBkaWdpdHMu