Atlantis (Simplified Version) 2025-05-15

In each era, add a unique improvement built on the ocean.
When adding population to ocean cells, it will automatically become a unique improvement instead of the original fishing boat.
【Currently, it needs to be used in conjunction with my another MOD-Unlock all unique buildings and improvements】

Now, all current era buildings can be built in the sea (more precisely, they can only be built in the sea).