theatre-js/theatre ? reverse-engineered prompt

I want a web motion design toolkit that feels like a visual animation editor plus a code friendly library. The main goal is to let someone create detailed, high fidelity animations in the browser, either by tweaking things in a studio style editor or by controlling them in code.

It should work for animating 3D scenes, regular HTML and SVG elements, small UI micro interactions, generative art setups, and really any JavaScript value that changes over time. I want timeline based editing, keyframes, smooth playback, and a nice workflow where I can design animations visually during development, then use the runtime part in the final app.

Please make it feel polished and reusable, not just a one off demo. Include a few clear examples that show 3D animation, DOM animation, and variable based animation, plus basic docs so it is easy to try. If you need details, look up the current public docs and examples online and match that overall product feel.