Elaborate in this context means planned out or carried out with great care. It can't be temporary because in this context it would mean lasting for a limited time, which is incorrect. It also can't be careless because in this context it would mean free from care. And it says that "nearly every page has a border of painted ines" and if they were carelss, it would be so refined to where they could tell that they were vines. I hope this helps even if a little!