Build a three-dimensional robot in a single self-contained index.html file, one that a visitor can inspect from every side. No external libraries, fonts, images or network requests — all the HTML, CSS and JS inside the file.

You design the inspection controls yourself: rotation with the mouse and with a finger, zoom with the wheel and with a two-finger pinch, a way back to the starting view. Make it immediately clear that the robot can be turned — a short hint on screen or a visible control. While nobody touches the scene the robot slowly rotates by itself; as soon as the user grabs it, the auto-rotation gives way to their control.

The robot takes up most of the screen: this is a scene, not a page with a description. Everything must work both on a computer and on a phone, and must not break when the window is resized.

Return ONLY the contents of index.html, complete, in a single code block.
