Which book series first popularized the use of 'house-specific' color-coded book jackets that became a major marketing and collectible strategy in young adult literature?

In the competitive world of book retail, packaging design has become increasingly important for standing out on crowded shelves. Publishers now invest significantly in cover art, special editions, and innovative packaging to attract readers in both physical and online stores. This poll tests your knowledge about a groundbreaking packaging innovation that transformed a particular literary phenomenon's market presence.

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Harry Potter series (Hogwarts house editions by Bloomsbury)
The Hunger Games trilogy (District-themed editions)
Percy Jackson series (Camp Half-Blood cabin editions)
Divergent trilogy (Faction-based collector editions)