Fireworks · claude-haiku-5.5

I'll build a single HTML file with a full-screen canvas and an animation loop that launches firework shells from the bottom of the screen toward wherever the user clicks, tracking each shell's position, trail, and timing in an array.

For the explosion, I'll spawn particles with velocity, gravity, and fading trails, using semi-transparent fill rectangles to create a motion-blur effect each frame. I'll add simple controls like a clear button and particle count display, exposing a state getter on window for testing, and handle canvas resizing for device pixel ratio while making sure clicks on the controls don't trigger a launch.

The screenshot shows the shell ascending correctly, launching from the bottom center with an ease-out curve, though the trail looks a bit sparse. I want to verify by clicking at a test point and inspecting the resulting state before clearing.

The click launched a trail rising from x=300, which looks right, but the first demo shell at x=600 still shows "shells 1" with zero particles, suggesting its burst hasn't triggered yet. This could just be the headless browser's frame loop running slowly between screenshots rather than an actual bug.

I'm puzzled that particles show 0 at screenshot time even though they should still be alive for a couple seconds post-burst — maybe the capture timing missed the window, or the particles are rendering too faint to register visually despite being counted.

Since the inspect tool can't evaluate JS, I can't read the live debug state directly. The stats consistently show zero particles even though ghost trails are visible, which suggests those trails are just leftover canvas fade from fill opacity rather than active particles — meaning bursts did occur but the particles died off quickly before the stats snapshot.

Given these limits, I think my best move is to capture a quick motion sequence right after a click, so I can actually watch the burst sequence happen frame by frame instead of relying on static snapshots.

The firework animation sequence looks right—launch, ascent, burst, particle spread, and fall all check out, with the zero-particle readings just being an artifact of inspecting immediately after launch. The faint ghosting effect is coming from the trail fade.

Now I should verify the Clear function actually clears the ghosts since it fills with a solid background rather than the semi-transparent wipe used for trails. Let me click Clear and inspect to confirm.

Clearing works correctly, and the fade trails are intentional and fine. I'm checking that pointer events are properly scoped so clicking controls doesn't interfere with canvas interactions, and it looks solid.

I haven't tested resize behavior, overlapping shells, or performance under load. Also, the shell launches straight up from the clicked x-column rather than diagonally toward the click point—technically matching "from bottom" but worth noting it's vertical rather than angled.