Okay kiddo, sometimes in politics, different groups of people with different ideas join together to form a team. It's like when you and your friends all want to play a game together, you work together to come up with a plan.
The pan-purple coalition is a group of political parties in Italy that have different ideas but they decided to work together. The "pan" part means they want to help all of Italy and the "purple" part means they want to focus on things like social justice and equality.
It's like if your friend likes pizza and another friend likes tacos, they may not agree on everything, but they can still work together to have a fun party with both pizza and tacos. That's what the pan-purple coalition is doing, they're working together to try to make Italy a better place for everyone.