Okay kiddo, imagine you're looking at a big, fancy building from a long time ago. It probably has lots of curves, and maybe some pointy parts too. Now imagine that same building, but it's covered in shiny metal and has bright neon lights outlining the shapes. That's what people mean when they talk about "raygun gothic" - it's a style that mixes old-fashioned curves and details with futuristic-looking materials and colors.
The name comes from science fiction stories and movies from a while ago, where they often had spaceships and other things that looked like they came from the future, but had a kind of retro feel to them too. The people who designed buildings and other things in this style wanted to create something that looked both old and new at the same time, which is why they used things like metal and neon lights to make traditional shapes look more modern.
Overall, raygun gothic is a style that mixes old and new in really cool and unique ways, and it's often associated with a kind of retro-futuristic look that people think is really neat!