3D scenes (closest thing to the DOM) and materials (closest thing to CSS) are several abstraction layers above what modern 3D APIs provide, this is more 'rendering/game engine' territory.

3D APIs are more on the level of 'draw this list of triangles, and the color of a specific pixel in the triangle is computed like this: (hundreds of lines of pixel shader code)" - but even this is slowly being being replaced by even lower level code which implements completely custom rendering pipelines entirely on the GPU.