Minimalist Alien Message Book Cover

Design a minimalist book cover for book_title by author_name. The background is a solid, warm off-white or cream color. At the top, display the title in large, bold, black sans-serif typography, stacked vertically with tight line spacing. Below the title, place a large, solid black square that occupies most of the central and lower-middle portion of the cover. Inside this black square, create a graphic pattern of white dots arranged in a grid-like structure. This dot pattern should transition from sparse, scattered points in the upper-left corner to a dense, uniform grid filling the bottom-right corner, creating a diagonal gradient effect. Intersperse small white plus signs (+) among the sparser dots in the upper-left area. At the very bottom of the cover, centered below the black square, write the author's name in smaller, spaced-out black capital letters.