Flat projection, spatial planes.

A source-backed orthographic CSS3D contract: the same OrthographicCamera frames DOM planes, orbit zoom stays bounded, view offsets can be applied and cleared, and resize updates the projection and renderer together.

This route claims the installed CSS3DRenderer/CSS3DObject scene-graph and orthographic camera/view-offset contract only. The official WebGL wireframe layer, lil-gui presentation, display-zoom limits, device coverage, performance calibration, context-loss/leak stress, and whole-example fidelity remain separate.

Sources: official CSS3D orthographic example · OrthographicCamera · CSS3DRenderer