I really like the design. There were two things I noticed that might be useful:
One is about the CSS. The main wrapper for your content seems to resize at various breakpoints, but the left margin decreases to zero in quite a few sizes and you haven’t added any padding. This might be intentional, but it seems like it shouldn’t be… maybe that is just me. It might be better to create a fluidly sized wrapper, here is a link with good advice about wrappers:
The other thing I noticed is that the two animated elements on the full width 3D scene don’t move along with the whole scene on mouseover, (the spinning octahedron and donut stay fixed while the scene moves in relation to the mouse). Again, maybe this is intentional, but is one of those things that seems like a visual bug.