The Trending Books feed often contains multiple books from the same series, which can take up a large portion of the list and reduce variety.

Instead, treat a series as a single entry by default. If several books from the same series are trending, show just one representative entry (for example, the highest-ranked or first book in the series), with an indication that the series contains other trending books.

This would:

• Increase the diversity of books shown in the Trending feed.
• Make it easier to discover new authors and series.
• Prevent popular long-running series from dominating the list.

Users could optionally expand a series to see the individual books if they're interested.