Your graphics are fun, and I'm sure they will be a success within your family. A couple of things: I would go for centering the page content. On the white sheet of the preview.html I would move the framing (header, coffee cups, brown lines) a bit in from the edges. You could think of using the background with a different sheet, one with no pattern, and the white sheet WITH the pattern on top of a unicolour background. The two of them together is a bit too much to rest your eyes on. (or rest MY eyes on. It's only my personal opinion.).
Good luck anyway.