Problem with the casting

I have not actually seen the show, and therefore if they stay true to the book in that sense, however, the looks of the actors and actresses themselves are wrong. If you actually read the book: Cassie has brown hair and blue eyes; Adam has red hair and blue-grey eyes; and Diana has blonde hair (but I don't remember the eye color).

I don't know if they stay true to the story of the books or not, but these details so obviously ignored from the book have made me against watching this show, since it is on Netflix.