Okay kiddo, so you know how when we build a house or a building, we have to think about how it looks and how it works? That's important because we want to make sure that it looks nice and is safe for people to live or work in.
Architectural theory is when people who design buildings think really hard about how to make them even better. They ask questions like "What does it mean for a building to be 'good'?" or "What kind of building would be best for the people who are going to use it?"
They also think about how buildings fit into the world around them, like how they relate to nature, other buildings, and the people who live and work nearby. They might even think about how our emotions are affected by the buildings we're in!
So basically, architectural theory is like really smart people thinking really hard about how to make buildings that are not just pretty, but also safe, useful, and inspiring for people who use them. It's kind of like a puzzle where they try to find the best way to put all the pieces together.