Create an animated pixel-art diorama of Paris at night, to serve as a looping background for a 10-hour lofi video on YouTube. Everything in a single HTML file (canvas + JavaScript, no libraries).

AMBIANCE AND COLORS
Go all out on the warm/cold contrast: a rainy night in midnight blue and violet, with pockets of warm light. The golden Eiffel Tower, lit windows, streetlamps, a café.

THE SCENE (from back to front)
- A dithered gradient sky (dithering in pixel art style), a moon with a halo, and several layers of clouds that scroll slowly, lit by the moon above and the city below.
- The Eiffel Tower in the center, golden, with its lattice structure, its 3 platforms and its antenna. Its beacon rotates and sweeps the sky. It sparkles regularly (white dots that blink everywhere), and a red light blinks at the very top.
- In the background, a line of Parisian rooftops with windows that turn on and off, the golden dome of the Invalides and the white Sacré-Cœur on its hill.
- A quay with plane trees and streetlamps.
- The Seine, with reflections of the tower and lampposts that ripple, long streaks of golden light, rain circles on the water, and a lit bateau-mouche that crosses occasionally.
- On the left, in the foreground, a Haussmannian building: wet zinc roof, chimney smoking and spitting sparks, a cat in a dormer window wagging its tail, a candlelit window flickering, a TV flickering blue, an wrought-iron balcony, a café with a red-striped awning and a "CAFÉ" neon sign that crackles occasionally.
- On the right, a Parisian streetlamp with a warm halo, which flickers sometimes.
- At the very bottom, a wrought-iron balustrade with planters.

EFFECTS
- Rain on 3 depths. The drops turn orange when they pass through a light, and they splash on the sills, the awning, and the balustrade.
- BILLS FALLING FROM THE SKY: 100 €, 50 €, and 20 € bills, on multiple depths. They flutter like leaves (they sway, rotate, flip over, and shine when facing forward).
- Smoke drifting with the wind, sparks, flickering lights, and 2 discreet lightning flashes in the clouds per loop.

TECHNICAL (important)
- Internal rendering at 480×270, scaled ×4 without smoothing (nearest neighbor), for a perfectly sharp 1920×1080 in fullscreen.
- The loop is PERFECT and lasts 4 minutes: every animation is a function of time modulo 240 s (integer frequencies, deterministic particles), so no jumps when it loops back.
- R key: records exactly one loop in 1920×1080, 60 fps, and downloads the video file (mp4 if possible, otherwise webm).
- S key: captures PNG in 1080p. F key or double-click: fullscreen. The cursor hides when the mouse isn't moving.
- Optimize to hold 60 fps: pre-rendered sprites, cached halos, and a canvas with the willReadFrequently option.