User wants a single-page web app in index.html using Tone.js. Must use local tone.min.js via <script src="tone.min.js"></script>. No external resources/CDNs. Need playable piano keyboard with mouse and computer keys, ADSR envelope synthesis, visual key feedback. Need self-contained index.html in current directory.
Plan:
1. List files to confirm tone.min.js present.
2. Build index.html with CSS for keyboard, white and black keys. layout.
3. JS: Create Tone.Synth with ADSR envelope (attack, decay, sustain, release). Map keyboard keys to notes (e.g., QWERTY row to white/black keys across two octaves). Mouse/touch support. Visual active class. Start audio context on interaction. Controls for ADSR sliders maybe.
Need make sure no external resources. Use pool: true? We'll just use synth.
MIDI: Could allow Web MIDI maybe but not necessary.
Need current date no matter. Let's create.

  Need write index.html. Let's design.

HTML structure:
- header, controls for ADSR (range inputs), volume, waveform select.
- keyboard container with keys generated via JS.
- instructions.

CSS: use flex for keyboard, key styles.

JS:
- Map of key bindings to notes. Use starting octave 3 and 4. Provide about 15 notes. Choose keyboard keys: z,x,c,v,b,n,m for C3..B3, q,w,e,r,t,y,u,i,o,p for C4..E5 etc. But maybe two octaves. Let's keep simple: `KeyA` C4? We can use `a s d f g h j k l ; '` for white keys C4..E5, plus `w e t y u o p` for sharps. That standard mapping. Then add lower octave using number row maybe. Simpler: one octave + some. We'll do two octaves:
Lower octave C3-B3: Z X C V B N M white, S D G H J sharps.
Upper octave C4-E5: Q W E R T Y U I O P [ ] white, 2 3 5 6 7 9 0 = sharps.
We can generate key elements for these. Active class mapping.

Use Tone.Synth with options:
oscillator: {type: selectedWave},
envelope: {attack, decay, sustain, release}.
Also master volume via Tone.Destination.volume.

Audio context: start on first pointerdown or keydown. Use `Tone.start()` and maybe `await Tone.start()`.

Mouse/touch: pointerdown triggers noteOn, pointerup noteOff, pointerleave cancel. Use `setPointerCapture`.

Keyboard: keydown triggers noteOn if not repeat, keyup triggers noteOff.

Visual feedback: active class changes background gradient.

Need ensure synth created after user interaction? We can create synth at load, Tone.Synth doesn't need context until play. Fine.

Sliders: attack 0.01–2, decay 0.1–2, sustain 0-1, release 0.1–3. Update synth.envelope.

Volume slider: -40 to 0 dB. Waveform select.

Frequency mapping: use Tone.Frequency(note).toFrequency. Keep note names.

Computer keys mapping constants.

Let's write. Use `<script src="tone.min.js"></script>` then `<script>`. Since tone.min.js exports global Tone.

Need note白键black CSS. Keyboard centered.

Let's ensure mobile: no user scaling? Not necessary.

No external fonts. Use system-ui font.

Visual key feedback color changes on active. Maybe black key active yellow, white key active cyan.

Add `touch-action:none` for keys.

Write file now.

   Need ensure black key positioning correct. I used offset property but not actually used; positions computed based on keyMap.indexOf(k) within whiteIndices find. Need verify mentally. For black key, whiteIndices array indices of white keys in keyMap. For C#3 (index 1), whiteIndices = [0,2,4,6,8,10,12,14,16,18,20,22,24,26,28]. findIndex(wi>1) => 1 (value2), prevWhiteIdx=0. left = (100/15)*0 + (100/15)*0.69 ~ 4.6%. Good.
D#3 index3 => prevWhite=2 => 13.3% + 4.6 = 17.9%. For F#3 index6 => prevWhite=4 => 26.7+4.6=31.3% etc. This seems correct.

But `keyMap.indexOf(k)` inside forEach works because k is object reference. Good.

One issue: I have offset property unused; not harmful. Could remove to clean, but not necessary.

Need check if `createSynth` recreates synth on controls after audio started; that's fine.

Potential bug: `synth.set({ envelope: { [id]: val } })` works for attack/decay/sustain/release. On changing oscillator type works.

PolySynth triggerAttack/triggerRelease with note names. Good.

Need ensure no external resources. We only load tone.min.js local. Good.

Maybe run local check with python http or just verify file exists. We can also open? Not possible. Could run a quick syntax check using Node? Tone.min.js needs browser. We can check if HTML is valid. Let's maybe run a simple grep for external http.

  Wait my grep was flawed src="tone includes t? It looked for src=\"[^t] skipping t. It found none. Good.

Now think about usability. Could update displayed ADSR values format: for attack 0.005 min and step 0.005; toFixed(3) shows 0.005. Good. Decay step 0.01 toFixed(2). Release step 0.05 toFixed(2). Sustain toFixed(2).

One concern: The `Tone.PolySynth` volume changes via `synth.volume.value` but in constructor we set volume option and also set volume.value. Fine. For oscillator update, PolySynth set should propagate.

Could simplify: when audio not yet started, controls don't affect future synth until createSynth called at start. That's fine.

Need possibly include aria labels? Not required.

Maybe we should remove unused `offset` property. User wants concise. Could keep or remove. Better remove unused to avoid confusion. Let's edit keyMap remove offset and comment. Also `whiteIndices` uses indexOf. Good.

Let's edit keyMap.

   Need double-check if there's any issue with key layout. Since `whiteIndices` is built by iterating `keyMap`, and black keys appended after? No, black keys positioned absolute. White keys are in normal flow flex `width: calc(100%/15)`. Good.

Each key label is the key letter. Good.

Potential issue: Clicking start button will create synth. Then clicking keys fine.

Could check file size. no need.

Let's produce final response. Use concise.