The user wants me to build a playable piano keyboard web app using tone.min.js (which is already in the current directory). Let me first check if the file exists, then build the complete single-page app.

Let me plan the app:
1. Load tone.min.js via <script src="tone.min.js">
2. Build a piano keyboard UI (CSS)
3. Use Tone.js for synthesis with ADSR envelope
4. Mouse click and keyboard controls
5. Visual key feedback (press/release animation)

Let me first check that tone.min.js is there.

The file exists. Now let me build the complete piano keyboard web app. Let me plan the features:

1. **Piano Keyboard Layout**: 2-3 octaves of piano keys (white and black keys)
2. **Mouse Interaction**: Click to play, release to stop
3. **Keyboard Interaction**: Computer keyboard keys mapped to piano notes
4. **Audio Synthesis**: Using Tone.js with a Synth that has ADSR envelope
5. **Visual Feedback**: Keys light up when pressed

Let me design the layout:
- White keys: C, D, E, F, G, A, B
- Black keys: C#, D#, F#, G#, A#
- I'll do 2 full octaves (C3 to B4, which is 24 notes? No, let me think... C4 to B5 maybe, or C3 to B4)

Actually, let me do 2 octaves: C4 to B5 (or C3 to B4). Let me use C4 to B5 which is 24 notes (14 white keys, 10 black keys).

For keyboard mapping, I'll use the bottom row of the QWERTY keyboard for the white keys and the row above for black keys, similar to many online piano apps.

Let me think about the mapping:
- C4 = A key
- C#4 = W
- D4 = S
- D#4 = E
- E4 = D
- F4 = F
- F#4 = T
- G4 = G
- G#4 = Y
- A4 = H
- A#4 = U
- B4 = J
- C5 = K
- etc.

Actually, let me use a more standard mapping. Let me use:

Row 1 (white keys): A S D F G H J K L ; (for one octave)
Row 2 (black keys): W E T Y U (for one octave)

For two octaves, I'll need to extend.

Let me use a simpler approach:
- Lower octave: Z X C V B N M (white keys C4-B4)
- Upper octave: A S D F G H J (white keys C5-B5)
- Black keys lower: S D G H J (shifted) - actually this gets confusing.

Let me use a standard mapping:
- C4 → a, C#4 → w, D4 → s, D#4 → e, E4 → d, F4 → f, F#4 → t, G4 → g, G#4 → y, A4 → h, A#4 → u, B4 → j
- C5 → k, C#5 → o, D5 → l, D#5 → p, E5 → ;, F5 → ', ... hmm this gets messy

Actually, let me use a common piano keyboard mapping. Many online pianos use:
- Bottom row (Z-M) for white keys of one octave starting from C
- Top row (Q-P) for another octave

Let me do:
Octave 1 (lower): C4-B4
- White: Z, X, C, V, B, N, M (C4, D4, E4, F4, G4, A4, B4)
- Black: S, D, G, H, J (C#4, D#4, F#4, G#4, A#4) — wait, these overlap with octave 2 whites

Let me simplify. I'll do 2 octaves with a clean layout.

White keys (2 octaves = 14 keys):
C4, D4, E4, F4, G4, A4, B4, C5, D5, E5, F5, G5, A5, B5

Black keys (2 octaves = 10 keys):
C#4, D#4, F#4, G#4, A#4, C#5, D#5, F#5, G#5, A#5

Keyboard mapping (using QWERTY row + home row):
- Row 1 (QWERTY upper): Q= C#4, W= D#4, E= F#4, R= G#4, T= A#4 (upper black keys first octave)
- Row 2 (home row): A= C4, S= D4, D= E4, F= F4, G= G4, H= A4, J= B4 (white keys first octave)
- Row 3 (lower): Z= C5, X= D5, C= E5, V= F5, B= G5, N= A5, M= B5 (white keys second octave)
- Row 4 (for black keys second octave): U= C#5, I= D#5, O= F#5, P= G#5, [= A#5

Hmm, let me think of a better mapping. Let me use a common one:

Actually, let me just use this mapping which is pretty standard:

White keys:
C4 → a
D4 → s
E4 → d
F4 → f
G4 → g
A4 → h
B4 → j
C5 → k
D5 → l
E5 → ;
F5 → '
G5 → (enter or something)

Hmm, getting awkward. Let me just do:

White keys: A S D F G H J K L ; (for C4-B4, and then C5)
Black keys: W E T Y U (for C#4, D#4, F#4, G#4, A#4)

But that only gives us one octave + 1 note. Let me extend:

Actually, I'll do a clean 2-octave setup. Let me use:

First octave (C4-B4):
- C4 → a (white)
- C#4 → w (black)
- D4 → s (white)
- D#4 → e (black)
- E4 → d (white)
- F4 → f (white)
- F#4 → t (black)
- G4 → g (white)
- G#4 → y (black)
- A4 → h (white)
- A#4 → u (black)
- B4 → j (white)

Second octave (C5-B5):
- C5 → k (white)
- C#5 → o (black)
- D5 → l (white)
- D#5 → p (black)
- E5 → ; (white)
- F5 → ' (white)
- F#5 → [ (black) — hmm, this is getting weird with special chars

Let me just use a different approach. I'll use:

First octave (C4-B4):
White keys: a, s, d, f, g, h, j
Black keys: w, e, t, y, u

Second octave (C5-B5):
White keys: z, x, c, v, b, n, m
Black keys: 2, 3, 5, 6, 7 (number row)

That's cleaner! Let me go with this.

Actually, I want to avoid number keys because they're less intuitive. Let me use:

First octave:
White: a, s, d, f, g, h, j
Black: w, e, -, t, y, u (no, - is awkward)

Alright, let me just go with a simple approach. I'll map:

Lower octave (C4-B4):
- White: a, s, d, f, g, h, j
- Black: w, e, -, t, y, u (hmm)

Let me just use this mapping which is clean:

First octave (C4-B4):
white: a, s, d, f, g, h, j
black: w, e, r, t, y (but r doesn't have a corresponding black key... actually F#4 is between F4 and G4, so r would work for F#4)

Wait, let me think about the piano layout:
C4 - D4 - E4 - F4 - G4 - A4 - B4
Black keys between: C#4 (between C&D), D#4 (between D&E), F#4 (between F&G), G#4 (between G&A), A#4 (between A&B)

Standard keyboard mapping often uses:
C D E F G A B → A S D F G H J
C# D# F# G# A# → W E T Y U

That's the most common mapping. Let me use that for the first octave, and for the second octave I'll use:

C5 D5 E5 F5 G5 A5 B5 → K L ; ' (or something)
C#5 D#5 F#5 G#5 A#5 → O P [ ] \ — nah

Let me simplify. I'll do 2 octaves with this mapping:

Octave 1 (C4-B4):
White: a, s, d, f, g, h, j
Black: w, e, t, y, u

Octave 2 (C5-B5):
White: z, x, c, v, b, n, m
Black: 2, 3, 5, 6, 7

Actually, let me just use a nice layout. I'll map it like this:

Octave 1:
C4 → a, C#4 → w, D4 → s, D#4 → e, E4 → d, F4 → f, F#4 → t, G4 → g, G#4 → y, A4 → h, A#4 → u, B4 → j

Octave 2:
C5 → k, C#5 → o, D5 → l, D#5 → p, E5 → ;, F5 → ', F#5 → [, G5 → ], G#5 → \, A5 → (nothing good)

OK this is getting too complicated. Let me just do ONE octave with a clean mapping, and use shift to move octave up/down, or just do 2 octaves with a reasonable mapping.

Actually, I'll do it cleanly. Let me use:

2 octaves, mapping:

Octave 1 (C4-B4):
White: a, s, d, f, g, h, j
Black: w, e, t, y, u

Octave 2 (C5-B5):  
White: z, x, c, v, b, n, m
Black: 2, 3, 5, 6, 7

This is clean and commonly used. The numbers 2,3,5,6,7 are above the ZXCVBNM row, making it natural.

Let me now write the full HTML file.

Let me test the file to make sure it loads correctly and there are no issues. Let me verify the file exists and try a quick syntax check.

All checks pass. Let me also quickly verify the tone.min.js is a valid script by parsing its exports:

Minor error in checking script but the important output is the notes array which looks correct. The app is complete. Let me provide a summary.

The file is complete and self-contained. Let me provide a summary of what was built.