nekrei/Seismic-Sim ? reverse-engineered prompt

Build me a web based earthquake simulator where I can pick a building and a real earthquake record, then watch the floors sway in 3D based on actual structural response instead of a fake animation.

I want the app to let me tweak things like building size, earthquake strength, distance, and depth, then show the results as the simulation runs, including floor displacement, spectra, transfer function, and a simple collapse mode when the structure fails. It should feel educational and interactive, with a clean setup panel, playback controls, event markers, and a responsive layout that still works well on mobile.

Please make it use a Python backend for the live calculations and serve a browser frontend with a realistic 3D building view. If you need current docs or examples for any libraries, look them up online. Also include a way to run it locally and a couple of example earthquake records or cached demo data so the app works right away.