<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Responsive Physics Simulation</title> <style> body { margin: 0; overflow: hidden; background: #f0f4f8; font-family: sans-serif; } canvas { display: block; } #controls { position: absolute; top: 20px; left: 20px; background: rgba(255, 255, 255, 0.9); padding: 15px; border-radius: 8px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); } </style> </head> <body> <div id="controls"> <h3>Gravity Lab</h3> <p...