Eternal Love -- PURPLE
Purple is often associated with royalty, nobility, power, and ambition. While those ideas don't really play a role in this book, I chose the color purple for a couple of reasons.
First, red (Chloe) + blue (Trent) = purple, and to me this cover is the culmination of Chloe and Trent's love.
Second, purple also symbolizes devotion--which Chloe and Trent have for one another--and magic, which starts to play a much larger role in the series in this book. Some sources say purple can also relate to hopes and dreams, and there are definitely a lot of those in this book.
While I'm not sharing the covers for books 4 and 5 just yet (for spoiler reasons), I will say that they follow the same theme as the first four books in that the colors were chosen for very specific reasons.