Which major marketing innovation in book cover design during the 1980s-90s significantly boosted retail sales by changing how consumers interacted with books in stores?

In the publishing industry, book covers are crucial marketing tools that can make or break a book's commercial success. In recent decades, publishers have evolved their cover design strategies to appeal to changing consumer preferences and shopping habits. This trivia question focuses on a significant shift in book cover design that revolutionized how readers interact with literature in retail environments.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

The introduction of embossed metallic lettering on covers
The widespread adoption of the 'stepback' cover (additional artwork revealed when opening the cover)
The implementation of the 'face-out' display model requiring more eye-catching cover designs
The standardization of author name size being larger than book titles