Just wanted to share/remind you about this information currently in game on how to copy spells from an old deck to an empty deck.
1) Equip the old deck with the spells you want in it in the Backpack Window of your Spellbook 2) Double click the spell deck with no cards in it in the Backpack Window of your Spellbook 3) You will get the prompt "Would you like to copy spells from your old deck to your empty deck?"
Shared this message because I've seen many people question why you don't get the prompt everytime.
To get the prompt to do it for you, you must make sure the empty deck is completely empty, this includes the treasure card side of the empty deck!