BARCELONA — A tide of emotion has washed over Catalonia in the past few days, over those who demand separation from Spain and those who oppose it. Graffiti has appeared overnight, proclaiming, “We are not Spanish.” Crowds have marched past gawking tourists, singing, “I am, I am, I am Spanish.”

One thing that unites them is that they have very little idea what an independent Catalonia would look like. Would it be readmitted to the European Union? Would it use a new currency? Would trade plummet? Would they be separated from their family members in Spain?

In the turbulence over Sunday’s referendum, there had been surprisingly little public debate about the practical effect of declaring independence. Spain’s heavy-handed response made the referendum into a battle over the right to vote, an issue over which there is far greater consensus in Catalonia.

With the referendum behind them, Catalans have begun to ask: What just happened? And what happens now?