Petals: 2D sprite blossoms instead of shader blobs

The procedural WebGL petals read as faint smudges. Replace with a 2D
canvas that pre-renders real notched sakura petal sprites (tip→base
gradient, soft central sheen, transparent edges) and blits falling,
rotating, swaying instances. Count scales with viewport; pauses when
hidden; skipped under prefers-reduced-motion.

Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd

scripts/gen_sounds.py

@@ -0,0 +1,165 @@
+#!/usr/bin/env python3
+"""Generate Petal's cute UI sound palette as small WAV assets.
+
+These are warm, rounded little sounds — bubble pops, water drops, soft bells —
+played when suggestions and companion bubbles appear. We synthesize them here
+(rather than ship someone else's clips) so they match the app's gentle aesthetic
+exactly and stay tiny. Output lands in web/src/assets/sounds/ where Vite bundles
+and fingerprints them into dist (and so into the embedded Go binary).
+
+Run:  python3 scripts/gen_sounds.py
+"""
+import math
+import os
+import struct
+import wave
+
+SR = 44100
+OUT = os.path.join(os.path.dirname(__file__), "..", "web", "src", "assets", "sounds")
+
+
+def env(n, attack, decay, total):
+    """Smooth attack + exponential decay envelope over `total` seconds."""
+    a = max(1, int(attack * SR))
+    out = []
+    for i in range(n):
+        t = i / SR
+        if i < a:
+            amp = i / a
+        else:
+            amp = math.exp(-(t - attack) / decay)
+        out.append(amp)
+    return out
+
+
+def sine(freq_at, n):
+    """Sine with a per-sample frequency function freq_at(t)->Hz (phase-accurate)."""
+    out = []
+    phase = 0.0
+    for i in range(n):
+        t = i / SR
+        f = freq_at(t)
+        phase += 2 * math.pi * f / SR
+        out.append(math.sin(phase))
+    return out
+
+
+def mix(*layers):
+    n = max(len(l) for l in layers)
+    out = [0.0] * n
+    for l in layers:
+        for i, v in enumerate(l):
+            out[i] += v
+    return out
+
+
+def soft_clip(s):
+    return [math.tanh(v * 1.2) for v in s]
+
+
+def normalize(s, peak=0.9):
+    m = max(1e-9, max(abs(v) for v in s))
+    g = peak / m
+    return [v * g for v in s]
+
+
+def write_wav(name, samples):
+    samples = soft_clip(samples)
+    samples = normalize(samples, 0.85)
+    # 4ms fade-out tail so nothing clicks at the end.
+    tail = int(0.004 * SR)
+    for i in range(tail):
+        samples[-1 - i] *= i / tail
+    os.makedirs(OUT, exist_ok=True)
+    path = os.path.join(OUT, name)
+    with wave.open(path, "w") as w:
+        w.setnchannels(1)
+        w.setsampwidth(2)
+        w.setframerate(SR)
+        frames = b"".join(struct.pack("<h", int(max(-1, min(1, v)) * 32767)) for v in samples)
+        w.writeframes(frames)
+    print(f"wrote {name}  ({len(samples)/SR*1000:.0f} ms, {len(frames)} bytes)")
+
+
+def apply_env(sig, e):
+    return [s * a for s, a in zip(sig, e)]
+
+
+def bubble_pop():
+    """A cute bubble 'bloop' — pitch swoops up fast then a rounded body."""
+    dur = 0.16
+    n = int(dur * SR)
+    # Rising swoop is the signature of a bubble.
+    body = sine(lambda t: 360 + 720 * (1 - math.exp(-t * 38)), n)
+    body = apply_env(body, env(n, 0.004, 0.05, dur))
+    # A soft octave shimmer on top.
+    shimmer = sine(lambda t: 1080 + 400 * (1 - math.exp(-t * 38)), n)
+    shimmer = apply_env(shimmer, env(n, 0.003, 0.03, dur))
+    shimmer = [v * 0.25 for v in shimmer]
+    return mix(body, shimmer)
+
+
+def droplet():
+    """A clean little water-drop ping — high, downward, watery tail."""
+    dur = 0.22
+    n = int(dur * SR)
+    main = sine(lambda t: 1500 * math.exp(-t * 3.2) + 760, n)
+    main = apply_env(main, env(n, 0.003, 0.06, dur))
+    # Tiny resonant echo for a wet feel.
+    echo = sine(lambda t: 980, n)
+    echo = apply_env(echo, env(n, 0.05, 0.07, dur))
+    echo = [v * 0.2 for v in echo]
+    return mix(main, droop_delay(echo, 0.04))
+
+
+def droop_delay(sig, delay_s):
+    d = int(delay_s * SR)
+    return [0.0] * d + sig
+
+
+def bell(freq, dur, partials=((1, 1.0), (2.01, 0.5), (2.78, 0.28), (4.1, 0.12))):
+    """A soft inharmonic bell tone (sum of slightly detuned partials)."""
+    n = int(dur * SR)
+    layers = []
+    for ratio, amp in partials:
+        s = sine(lambda t, f=freq * ratio: f, n)
+        s = apply_env(s, env(n, 0.005, dur * 0.45, dur))
+        layers.append([v * amp for v in s])
+    return mix(*layers)
+
+
+def chime():
+    """Two gentle bell notes a soft fifth apart."""
+    a = bell(784, 0.42)  # G5
+    b = bell(1175, 0.40)  # D6
+    b = droop_delay(b, 0.10)
+    return mix(a, [v * 0.85 for v in b])
+
+
+def shimmer():
+    """Three quick ascending sparkles — glockenspiel-ish."""
+    notes = [988, 1319, 1976]  # B5, E6, B6
+    layers = []
+    for i, f in enumerate(notes):
+        s = bell(f, 0.30, partials=((1, 1.0), (2.7, 0.3), (5.1, 0.1)))
+        layers.append(droop_delay([v * 0.8 for v in s], 0.06 * i))
+    return mix(*layers)
+
+
+def cheer():
+    """A happy little major arpeggio C5-E5-G5-C6 on bells."""
+    notes = [523, 659, 784, 1047]
+    layers = []
+    for i, f in enumerate(notes):
+        s = bell(f, 0.36)
+        layers.append(droop_delay([v * 0.8 for v in s], 0.075 * i))
+    return mix(*layers)
+
+
+if __name__ == "__main__":
+    write_wav("pop.wav", bubble_pop())
+    write_wav("droplet.wav", droplet())
+    write_wav("chime.wav", chime())
+    write_wav("shimmer.wav", shimmer())
+    write_wav("cheer.wav", cheer())
+    print("done →", os.path.normpath(OUT))

web/src/App.tsx

@@ -13,6 +13,8 @@ import { StatusBar } from './components/StatusBar/StatusBar'
 import { PetalCompanion } from './components/Companion/PetalCompanion'
 import { UpdateBanner } from './components/UpdateBanner/UpdateBanner'
 import { useVersionWatch } from './hooks/useVersionWatch'
+import { PetalFall } from './effects/PetalFall'
+import { playSuggestionSound } from './audio/sounds'
 
 export default function App() {
   const updateAvailable = useVersionWatch()
@@ -309,8 +311,34 @@ export default function App() {
     [removeSuggestion],
   )
 
+  // Play a soft sound when freshly-checked suggestions arrive — one per distinct
+  // new type, lightly staggered so a batch reads as a little melody rather than
+  // a pile-up. We track which ids we've already chimed for, and only chime for
+  // recently-created suggestions so opening a doc with old pending advice stays
+  // silent (the existing set was created in a past session).
+  const chimedRef = useRef<Set<string>>(new Set())
+  useEffect(() => {
+    const fresh = suggestions.filter((s) => !chimedRef.current.has(s.id))
+    fresh.forEach((s) => chimedRef.current.add(s.id))
+    const justMade = fresh.filter(
+      (s) => Date.now() - new Date(s.created_at).getTime() < 12_000,
+    )
+    if (justMade.length === 0) return
+    const types = [...new Set(justMade.map((s) => s.type))].slice(0, 3)
+    const timers = types.map((t, i) =>
+      window.setTimeout(() => playSuggestionSound(t), i * 150),
+    )
+    return () => timers.forEach((id) => window.clearTimeout(id))
+  }, [suggestions])
+
+  // Forget chimed ids when switching documents so the set can't grow unbounded.
+  useEffect(() => {
+    chimedRef.current = new Set()
+  }, [currentDoc?.id])
+
   return (
     <div className="flex h-full flex-col">
+      <PetalFall />
       <header
         onMouseDown={handleChromeDown}
         className="petal-no-print flex h-12 shrink-0 items-center gap-2 px-5"

web/src/audio/sounds.ts

@@ -0,0 +1,174 @@
+// Petal's cute sound palette. The actual tones live as tiny WAV assets in
+// ./assets (generated by scripts/gen_sounds.py — warm bubble pops, water drops,
+// and soft bells tuned to match the app's gentle look). Vite fingerprints and
+// bundles them into dist, so they ride along inside the single Go binary; here
+// we just fetch + decode them once and play them through a Web Audio bus with a
+// soft master volume. The whole thing is opt-out-able and the mute choice
+// persists in localStorage so it survives reloads.
+
+import popUrl from '../assets/sounds/pop.wav'
+import dropletUrl from '../assets/sounds/droplet.wav'
+import chimeUrl from '../assets/sounds/chime.wav'
+import shimmerUrl from '../assets/sounds/shimmer.wav'
+import cheerUrl from '../assets/sounds/cheer.wav'
+
+const STORAGE_KEY = 'petal.sound'
+
+// Master volume — deliberately gentle. These are background delights, not alerts.
+const MASTER_GAIN = 0.5
+
+export type SoundName =
+  | 'pop' // a soft bubble pop — the signature "something arrived"
+  | 'droplet' // a single rounded water-drop ping
+  | 'chime' // a gentle two-note bell
+  | 'shimmer' // three quick ascending sparkles
+  | 'cheer' // a happy little major arpeggio (accepts, milestones)
+
+const SOURCES: Record<SoundName, string> = {
+  pop: popUrl,
+  droplet: dropletUrl,
+  chime: chimeUrl,
+  shimmer: shimmerUrl,
+  cheer: cheerUrl,
+}
+
+let ctx: AudioContext | null = null
+let master: GainNode | null = null
+const buffers = new Map<SoundName, AudioBuffer>()
+let enabled = readEnabled()
+const listeners = new Set<(on: boolean) => void>()
+
+function readEnabled(): boolean {
+  try {
+    return localStorage.getItem(STORAGE_KEY) !== 'off'
+  } catch {
+    return true
+  }
+}
+
+export function isSoundEnabled(): boolean {
+  return enabled
+}
+
+export function setSoundEnabled(on: boolean): void {
+  enabled = on
+  try {
+    localStorage.setItem(STORAGE_KEY, on ? 'on' : 'off')
+  } catch {
+    /* private mode — choice just won't persist */
+  }
+  listeners.forEach((fn) => fn(on))
+  // Touching the context on enable doubles as a user-gesture unlock + warm-up.
+  if (on) void ensureContext()
+}
+
+export function onSoundEnabledChange(fn: (on: boolean) => void): () => void {
+  listeners.add(fn)
+  return () => listeners.delete(fn)
+}
+
+// Lazily create the AudioContext (browsers require a user gesture before audio
+// can play; the first play() after a click will succeed, earlier ones resume).
+async function ensureContext(): Promise<AudioContext | null> {
+  if (typeof window === 'undefined') return null
+  const AC: typeof AudioContext | undefined =
+    window.AudioContext ??
+    (window as unknown as { webkitAudioContext?: typeof AudioContext }).webkitAudioContext
+  if (!AC) return null
+  if (!ctx) {
+    ctx = new AC()
+    master = ctx.createGain()
+    master.gain.value = MASTER_GAIN
+    // A gentle soft-clip so stacked sounds never crackle.
+    const shaper = ctx.createWaveShaper()
+    shaper.curve = softClipCurve()
+    master.connect(shaper)
+    shaper.connect(ctx.destination)
+  }
+  if (ctx.state === 'suspended') {
+    try {
+      await ctx.resume()
+    } catch {
+      /* will retry on the next gesture */
+    }
+  }
+  return ctx
+}
+
+function softClipCurve(): Float32Array<ArrayBuffer> {
+  const n = 1024
+  const curve = new Float32Array(new ArrayBuffer(n * 4))
+  for (let i = 0; i < n; i++) {
+    const x = (i / (n - 1)) * 2 - 1
+    curve[i] = Math.tanh(x * 1.2)
+  }
+  return curve
+}
+
+// Fetch + decode one sound, caching the decoded buffer for instant replay.
+async function load(name: SoundName, audio: AudioContext): Promise<AudioBuffer | null> {
+  const cached = buffers.get(name)
+  if (cached) return cached
+  try {
+    const res = await fetch(SOURCES[name])
+    const bytes = await res.arrayBuffer()
+    const buf = await audio.decodeAudioData(bytes)
+    buffers.set(name, buf)
+    return buf
+  } catch {
+    return null // asset missing / decode failed — sound just won't play
+  }
+}
+
+// Warm the cache so the first real play is instant.
+async function prime(): Promise<void> {
+  const audio = await ensureContext()
+  if (!audio) return
+  await Promise.all((Object.keys(SOURCES) as SoundName[]).map((n) => load(n, audio)))
+}
+
+// Fire a sound. No-op when muted or audio is unavailable. Never throws — a
+// delight that fails should fail silently.
+export function playSound(name: SoundName): void {
+  if (!enabled) return
+  void (async () => {
+    const audio = await ensureContext()
+    if (!audio || !master || audio.state !== 'running') return
+    const buf = await load(name, audio)
+    if (!buf) return
+    try {
+      const src = audio.createBufferSource()
+      src.buffer = buf
+      src.connect(master)
+      src.start()
+    } catch {
+      /* audio glitch — ignore */
+    }
+  })()
+}
+
+// Map an editor suggestion type to its sound, so each kind of help has its own
+// little voice (grammar pops like a bubble, idioms chime, etc.).
+const SUGGESTION_SOUND: Record<string, SoundName> = {
+  grammar: 'pop',
+  phrasing: 'droplet',
+  idiom: 'chime',
+  clarity: 'shimmer',
+  voice: 'droplet',
+}
+
+export function playSuggestionSound(type: string): void {
+  playSound(SUGGESTION_SOUND[type] ?? 'pop')
+}
+
+// Unlock + warm audio on the first user gesture so the very first sound isn't
+// dropped by the browser's autoplay policy. Self-removing.
+if (typeof window !== 'undefined') {
+  const unlock = () => {
+    void prime()
+    window.removeEventListener('pointerdown', unlock)
+    window.removeEventListener('keydown', unlock)
+  }
+  window.addEventListener('pointerdown', unlock)
+  window.addEventListener('keydown', unlock)
+}

web/src/components/Companion/useCompanion.ts

@@ -12,6 +12,7 @@ import {
   type Line,
 } from './tips'
 import { analyzeProse } from './prose'
+import { playSound } from '../../audio/sounds'
 
 // The kitten's expression. Maps to a Lottie animation when assets are present,
 // otherwise to an emoji placeholder (see PetalCompanion).
@@ -95,6 +96,11 @@ export function useCompanion({ wordCount, saveStatus, editTick, acceptTick, text
       lastProactive.current = t
     }
     sleeping.current = false
+    // A soft sound to match the bubble's mood — celebrations cheer, gentle
+    // cheers sparkle, break nudges chime, and tips give a little bubble pop.
+    playSound(
+      opts?.celebrate ? 'cheer' : b.tone === 'cheer' ? 'shimmer' : b.tone === 'break' ? 'chime' : 'pop',
+    )
     setBubble(b)
     setMood(opts?.celebrate ? 'celebrate' : 'talking')
     clearTimeout(bubbleTimer.current)

web/src/components/StatusBar/SoundToggle.tsx

@@ -0,0 +1,37 @@
+import { useEffect, useState } from 'react'
+import { isSoundEnabled, onSoundEnabledChange, playSound, setSoundEnabled } from '../../audio/sounds'
+
+// A tiny mute toggle for Petal's cute sounds, tucked at the right of the status
+// bar. Bilingual tooltip (she reads Mandarin first), and a soft confirming pop
+// when sounds are turned back on so the choice is audible.
+export function SoundToggle() {
+  const [on, setOn] = useState(isSoundEnabled)
+
+  // Stay in sync if the setting is flipped elsewhere.
+  useEffect(() => onSoundEnabledChange(setOn), [])
+
+  const toggle = () => {
+    const next = !on
+    setSoundEnabled(next)
+    setOn(next)
+    if (next) playSound('pop') // a little hello when re-enabled
+  }
+
+  return (
+    <button
+      type="button"
+      onClick={toggle}
+      aria-pressed={on}
+      title={on ? '声音开 · Sounds on' : '声音关 · Sounds off'}
+      aria-label={on ? 'Mute Petal sounds' : 'Unmute Petal sounds'}
+      className="rounded-full px-1.5 py-0.5 transition-colors"
+      style={{ color: on ? 'var(--color-accent)' : 'var(--color-muted)', lineHeight: 1 }}
+      onMouseEnter={(e) => (e.currentTarget.style.color = 'var(--color-accent-hover)')}
+      onMouseLeave={(e) =>
+        (e.currentTarget.style.color = on ? 'var(--color-accent)' : 'var(--color-muted)')
+      }
+    >
+      <span aria-hidden>{on ? '🔔' : '🔕'}</span>
+    </button>
+  )
+}

web/src/components/StatusBar/StatusBar.tsx

@@ -1,6 +1,7 @@
 import { useEffect, useRef, useState } from 'react'
 import type { SaveStatus } from '../../hooks/useAutoSave'
 import { StatsPanel } from './StatsPanel'
+import { SoundToggle } from './SoundToggle'
 
 interface Props {
   wordCount: number
@@ -120,6 +121,9 @@ export function StatusBar({ wordCount, text, saveStatus, checking, voicing, llmD
           </span>
         </>
       )}
+      <div className="ml-auto">
+        <SoundToggle />
+      </div>
     </footer>
   )
 }

web/src/effects/PetalFall.tsx

@@ -0,0 +1,200 @@
+import { useEffect, useRef } from 'react'
+
+// PetalFall is the cozy ambient layer: a fixed, non-interactive 2D canvas that
+// drifts soft cherry-blossom petals down the page. Each petal is a real
+// petal-shaped sprite (notched sakura silhouette with a gentle gradient and
+// soft alpha), pre-rendered once per color and then blitted many times with
+// rotation + sway. It sits behind the chrome, ignores pointer events, pauses
+// when the tab is hidden, and renders nothing for prefers-reduced-motion.
+
+// Saturated-but-soft blossom colors. Each petal fades from a light, near-white
+// tip to its color at the base, so it reads as a real petal rather than a blob.
+const PALETTE: { r: number; g: number; b: number }[] = [
+  { r: 255, g: 150, b: 190 }, // rose pink
+  { r: 255, g: 184, b: 205 }, // pale blossom
+  { r: 255, g: 158, b: 130 }, // warm peach
+  { r: 209, g: 160, b: 255 }, // lavender
+  { r: 255, g: 122, b: 172 }, // deep rose
+]
+
+const SPRITE_PX = 160 // off-screen render resolution per petal sprite
+
+function rgba(c: { r: number; g: number; b: number }, a: number): string {
+  return `rgba(${Math.round(c.r)}, ${Math.round(c.g)}, ${Math.round(c.b)}, ${a})`
+}
+function mixWhite(c: { r: number; g: number; b: number }, t: number) {
+  return { r: c.r + (255 - c.r) * t, g: c.g + (255 - c.g) * t, b: c.b + (255 - c.b) * t }
+}
+function scale(c: { r: number; g: number; b: number }, t: number) {
+  return { r: c.r * t, g: c.g * t, b: c.b * t }
+}
+
+// Draw one petal sprite: a notched sakura silhouette filled with a tip→base
+// gradient and a faint central highlight, on a transparent canvas.
+function makeSprite(color: { r: number; g: number; b: number }): HTMLCanvasElement {
+  const s = SPRITE_PX
+  const cv = document.createElement('canvas')
+  cv.width = s
+  cv.height = s
+  const g = cv.getContext('2d')!
+  g.translate(s / 2, s / 2)
+
+  const hw = s * 0.3 // half width
+  const hh = s * 0.44 // half height
+
+  g.beginPath()
+  g.moveTo(0, hh) // pointed base
+  g.bezierCurveTo(hw, hh * 0.42, hw * 0.92, -hh * 0.52, hw * 0.2, -hh * 0.92) // right side → near tip
+  g.quadraticCurveTo(0, -hh * 0.72, -hw * 0.2, -hh * 0.92) // the sakura notch
+  g.bezierCurveTo(-hw * 0.92, -hh * 0.52, -hw, hh * 0.42, 0, hh) // left side → base
+  g.closePath()
+
+  const grad = g.createLinearGradient(0, -hh, 0, hh)
+  grad.addColorStop(0, rgba(mixWhite(color, 0.55), 0.78)) // light, soft tip
+  grad.addColorStop(0.45, rgba(color, 0.88))
+  grad.addColorStop(1, rgba(scale(color, 0.8), 0.95)) // deeper base
+  g.fillStyle = grad
+  g.fill()
+
+  // A soft white sheen down the centre for a delicate, glossy feel.
+  const sheen = g.createLinearGradient(-hw * 0.3, 0, hw * 0.3, 0)
+  sheen.addColorStop(0, 'rgba(255,255,255,0)')
+  sheen.addColorStop(0.5, 'rgba(255,255,255,0.28)')
+  sheen.addColorStop(1, 'rgba(255,255,255,0)')
+  g.fillStyle = sheen
+  g.fill()
+
+  return cv
+}
+
+interface Petal {
+  baseX: number
+  y: number
+  size: number
+  vy: number // fall speed (px/s)
+  angle: number
+  spin: number // rad/s
+  swayAmp: number
+  swayFreq: number
+  swayPhase: number
+  alpha: number
+  sprite: number
+}
+
+export function PetalFall() {
+  const canvasRef = useRef<HTMLCanvasElement>(null)
+
+  useEffect(() => {
+    const reduce =
+      typeof window !== 'undefined' &&
+      window.matchMedia?.('(prefers-reduced-motion: reduce)').matches
+    if (reduce) return // respect users who don't want ambient motion
+
+    const el = canvasRef.current
+    if (!el) return
+    const c2d = el.getContext('2d')
+    if (!c2d) return
+    // Non-null aliases so the render closures keep the narrowed types.
+    const canvas = el
+    const ctx = c2d
+
+    const sprites = PALETTE.map(makeSprite)
+    const dpr = Math.min(window.devicePixelRatio || 1, 2)
+    let W = window.innerWidth
+    let H = window.innerHeight
+
+    // Scale petal count to the viewport so it stays sparse and gentle.
+    const count = Math.round(Math.min(46, Math.max(16, (W * H) / 46000)))
+    const rnd = (a: number, b: number) => a + Math.random() * (b - a)
+
+    const spawn = (initial: boolean): Petal => ({
+      baseX: rnd(0, W),
+      y: initial ? rnd(-H, H) : rnd(-60, -20),
+      size: rnd(16, 38),
+      vy: rnd(22, 52),
+      angle: rnd(0, Math.PI * 2),
+      spin: rnd(-0.9, 0.9),
+      swayAmp: rnd(14, 42),
+      swayFreq: rnd(0.3, 0.85),
+      swayPhase: rnd(0, Math.PI * 2),
+      alpha: rnd(0.5, 0.82),
+      sprite: Math.floor(Math.random() * sprites.length),
+    })
+
+    let petals = Array.from({ length: count }, () => spawn(true))
+
+    function resize() {
+      W = window.innerWidth
+      H = window.innerHeight
+      canvas.width = Math.floor(W * dpr)
+      canvas.height = Math.floor(H * dpr)
+      canvas.style.width = `${W}px`
+      canvas.style.height = `${H}px`
+      ctx.setTransform(dpr, 0, 0, dpr, 0, 0)
+    }
+    resize()
+    window.addEventListener('resize', resize)
+
+    let raf = 0
+    let running = true
+    let last = performance.now()
+
+    function frame(now: number) {
+      if (!running) return
+      const dt = Math.min(0.05, (now - last) / 1000) // clamp big gaps (tab wake)
+      last = now
+      const t = now / 1000
+      ctx.clearRect(0, 0, W, H)
+
+      for (const p of petals) {
+        p.y += p.vy * dt
+        p.angle += p.spin * dt
+        const x = p.baseX + p.swayAmp * Math.sin(t * p.swayFreq + p.swayPhase)
+
+        // Recycle once fully past the bottom.
+        if (p.y - p.size > H) {
+          Object.assign(p, spawn(false))
+          continue
+        }
+
+        ctx.save()
+        ctx.translate(x, p.y)
+        ctx.rotate(p.angle)
+        ctx.globalAlpha = p.alpha
+        ctx.drawImage(sprites[p.sprite], -p.size / 2, -p.size / 2, p.size, p.size)
+        ctx.restore()
+      }
+      raf = requestAnimationFrame(frame)
+    }
+
+    const onVisibility = () => {
+      if (document.hidden) {
+        running = false
+        cancelAnimationFrame(raf)
+      } else if (!running) {
+        running = true
+        last = performance.now()
+        raf = requestAnimationFrame(frame)
+      }
+    }
+    document.addEventListener('visibilitychange', onVisibility)
+    raf = requestAnimationFrame(frame)
+
+    return () => {
+      running = false
+      cancelAnimationFrame(raf)
+      window.removeEventListener('resize', resize)
+      document.removeEventListener('visibilitychange', onVisibility)
+      petals = []
+    }
+  }, [])
+
+  return (
+    <canvas
+      ref={canvasRef}
+      aria-hidden
+      className="petal-fall pointer-events-none fixed inset-0"
+      style={{ zIndex: 20 }}
+    />
+  )
+}

web/src/index.css

@@ -382,7 +382,31 @@ button, a, input {
    only the title and the writing itself reach the page. This is Petal's PDF
    path — it uses the browser's own fonts, so CJK renders correctly with no
    server-side font embedding. */
+/* --- Ambient falling petals -------------------------------------------------
+   The WebGL petal layer is a fixed, non-interactive overlay that drifts soft
+   blossoms over the page. Kept gentle (low opacity) so it never competes with
+   the writing. It hides itself in print and is skipped entirely for users who
+   prefer reduced motion (the component renders nothing in that case). */
+.petal-fall {
+  opacity: 1;
+}
+
+/* Honor reduced-motion globally: still the looping ambient animations and drop
+   the petal layer. One-shot entrance/feedback animations are left intact. */
+@media (prefers-reduced-motion: reduce) {
+  .petal-fall {
+    display: none !important;
+  }
+  .petal-bob,
+  .petal-bob-slow,
+  .petal-zzz,
+  .petal-checkpoint-dot {
+    animation: none !important;
+  }
+}
+
 @media print {
+  .petal-fall,
   .petal-no-print,
   .petal-sidebar,
   .petal-suggestion-card,

web/src/vite-env.d.ts

@@ -0,0 +1 @@
+/// <reference types="vite/client" />