A shadow card is usually the card left at the bottom of the deck after you pull your spread.
I think of it as the underlying energy at work — something shaping everything else, an unseen factor, or an extra layer to keep in mind. Sometimes it shows up like encouragement or a short message that ties the reading together.
It depends on the question and context, but for me it's a clarifying card that helps flesh out and deepen the rest of the spread.
