Make a browser game in one HTML file: a paper airplane gliding through a city at dusk. The player steers the plane between rooftops, through open windows and under bridges, catching warm lights while the wind pushes back. A run lasts about two minutes and ends on a hill above the city where kites are flying, with a short ending scene and a score. Include a title screen, keyboard and touch controls, and sound made in code. It should feel like a small indie game someone would share, not a tech demo. 3D is welcome. You may use Three.js, but put it inside the file (no CDN links), so it opens offline with no network requests. No images, no other libraries. Write it in one go: don't open it in a browser or test it. Just deliver the file.