The user wants me to create a fireworks display web app with:
1. Full-screen canvas
2. Clicks launch fireworks shells
3. Shells explode into particles
4. Particles have gravity
5. Particles fade out

I need to create a single self-contained HTML file with:
- No external resources
- CSS in <style> tag
- JS in <script> tag
- Inline, not separate files

Let me write this code:

1. Set up a full-screen canvas
2. Create a Firework class that handles the rocket going up
3. Create a Particle class for the explosion
4. Handle clicks to launch fireworks
5. Add gravity and fading effects
6. Add some nice visual styling

Let me code this up.

Successfully created the index.html file. Let me summarize what I built:

1. A full-screen canvas with black background
2. A Firework class that:
   - Launches from bottom center to target point
   - Tracks coordinates for trailing effect
   - Explodes at target
3. A Particle class that:
   - Explodes in all directions from impact point
   - Has gravity (falls downward)
   - Has friction (slows down)
   - Fades out over time
   - Has trail effect
4. Click/touch events launch fireworks
5. Color scheme uses vibrant HSL colors
6. Uses global composite operations for blending effects

The app is self-contained with no external resources.