Greasy Hands Scroller

@unknown: Holy shit, Gemini 3 just helped me build an application that allows me to scroll content on my computer with my fingers IN THE AIR using hand tracking. Introducing "Greasy Hand", perfect for when you're cooking and need to scroll the recipe but don't wanna touch the computer. https://x.com/zarazhangrui/status/1992092536530493551/video/1 @unknown: Prompt: I want to build a 'Touch-Free Recipe Scroller' using Python on my laptop. Can you write a complete script and a step-by-step guide for a beginner? The Goal:An app that uses my webcam to track my hand. When I hold my index finger at the top of the screen, it scrolls the computer screen UP. When I hold it at the bottom, it scrolls DOWN. Technical Requirements: Use MediaPipe for hand tracking and OpenCV for the camera. Use PyAutoGUI to handle the actual scrolling. Crucial: Add a 'cooldown' or timer logic so the scrolling is rhythmic and smooth, not jerky or too fast. Draw green/red lines on the screen so I know where the scroll zones are. Allow me to quit the app by pressing 'q'. Instructions Needed: Provide the full Python code in one block. Tell me exactly which libraries to install via terminal. (if you run into errors, just screenshot and send to Gemini)