I need to create a single-page web app with a playable piano keyboard using the pre-provided tone.min.js library. The requirements are:

1. Single file: index.html with inline CSS and JS
2. Use the pre-provided tone.min.js (no CDN)
3. Piano keyboard controlled by mouse and computer keys
4. ADSR envelope for note synthesis
5. Visual key feedback when playing

Let me first check what's in the current directory to confirm tone.min.js is present.

Good, tone.min.js is present. Now I need to create a piano keyboard web app. I'll design:

1. A visual piano keyboard with white and black keys
2. Mouse click/touch support for playing notes
3. Computer keyboard mapping (like using keys A-K for white keys, W-E-T-Y-U for black keys)
4. ADSR envelope configuration for realistic piano sound
5. Visual feedback when keys are pressed (color change)
6. Use Tone.js synthesizer for sound generation

Let me create the index.html file with all the required functionality.

Perfect! I've created a comprehensive piano keyboard web app with all the requested features:

1. **Single self-contained file**: All CSS and JavaScript are inline in index.html
2. **Uses pre-provided tone.min.js**: Loaded with a simple script tag
3. **Playable piano keyboard**: 
   - Visual representation with white and black keys
   - 17 keys covering one and a half octaves (C to E)
   - Proper piano layout with black keys positioned correctly

4. **Mouse and keyboard control**:
   - Click/tap keys with mouse or touch
   - Computer keyboard mapping (A-K for white keys, W-E-T-Y-U-O-P for black keys)
   - Z/X keys for octave changing

5. **ADSR envelope**: 
   - Adjustable Attack, Decay, Sustain, and Release parameters
   - Real-time control with sliders
   - Visual feedback showing current values

6. **Visual key feedback**:
   - Keys change color when pressed (blue tint)
   - Subtle animation with transform and shadow
   - Active state management

7. **Additional features**:
   - Volume control
   - Octave selector (1-7)
   - Responsive design
   - Touch support for mobile devices
   - Professional gradient design
   - Clear keyboard mapping instructions

The app uses Tone.js PolySynth with a triangle oscillator for a pleasant piano-like sound. The ADSR envelope provides realistic note articulation, and the visual feedback makes it clear which notes are being played.