Okay, here is a basic structure.

Okay, let's add some basic visuals and make the canvas show something. This uses the 2D canvas API for now to draw a simple background, as a full 3D setup requires more complex libraries.

Okay, switching to a proper 3D setup using the Three.js library. This will create a basic 3D scene with a ground plane and a cube.

Okay, let's enhance the visuals significantly using Three.js features for a more professional look. This includes better lighting, shadows, a skybox, basic environment elements, and camera controls.

Okay, I've removed the error message from the loading screen and translated the UI and messages into Polish.