diff --git a/CLAUDE.md b/CLAUDE.md
index 08d298c..0bc1e0d 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -5,98 +5,120 @@ A custom mastering toolkit that provides metrics to evaluate audio masterings th
 ## Current Implementation
 
 ### Core Features
-- **Audio Analysis**: Uses librosa to analyze audio files (MP3/WAV support)
+- **Audio Analysis**: Uses librosa to analyze audio files (MP3/WAV/FLAC support)
 - **Power Visualization**: Generates colorized power magnitude graphs over time
 - **Metadata Extraction**: Reads ID3 tags from MP3 files for better file identification
-- **GUI Foundation**: Basic PyQt5 drag-and-drop interface (work in progress)
+- **Modular GUI Architecture**: Complete PyQt5 interface with drag-and-drop and file dialog support
+- **Font Management**: Comprehensive CJK-compatible font system with user-provided font support
+- **Threading & Logging**: Robust background processing with detailed logging system
 
 ### Technical Stack
 - **Audio Processing**: librosa, numpy
-- **Visualization**: matplotlib with custom colormaps
-- **GUI Framework**: PyQt5 (drag-and-drop functionality)
-- **Metadata**: mutagen for MP3 tag reading
+- **Visualization**: matplotlib with custom colormaps and embedded Qt widgets
+- **GUI Framework**: PyQt5 with modular widget architecture
+- **Metadata**: mutagen for audio tag reading
+- **Font Support**: Custom font loading system with CJK fallback
 
 ### Key Components
 
-#### `master_core.py`
-- `AudioFile` class: Main audio processing class
-  - Loads audio files and extracts basic metrics (max/avg amplitude, BPM)
-  - `get_energy_levels_over_time()`: Calculates RMS power over rolling windows
-  - `plot_energy_levels_over_time()`: Creates colorized power graphs with automatic headroom detection
-- `analyze_track_librosa()`: Legacy analysis function (dBFS calculations)
-- File processing from `files.txt` configuration
-
 #### `main.py`
-- PyQt5 drag-and-drop interface
-- Currently displays file paths but doesn't integrate with analysis functions
-- Placeholder for GUI integration
+- Complete GUI application with modular architecture
+- Drag-and-drop and file dialog support for audio files
+- Integrated font control system
+- Real-time analysis display and file management
 
-#### `files.txt`
-- Configuration file listing audio files to analyze
-- Supports comments (`;` and `#` prefixed lines)
-- Currently contains various music file paths
+#### `analysis_results_manager.py`
+- Background threading for audio analysis
+- Results caching and management
+- Progress tracking and error handling
+
+#### `audio_visualization_widget.py`
+- Embedded matplotlib visualization with Qt integration
+- Real-time plot updates and status display
+
+#### `font_control_widget.py` & `font_manager.py`
+- Unified font control system with clustered interface
+- Auto-detection of custom fonts from `fonts/` directory
+- System font discovery and CJK compatibility
+- Auto-regeneration of plots when fonts change
+
+#### `master_core.py`
+- Core audio analysis functionality
+- `AudioFile` class with comprehensive metrics extraction
+- RMS power analysis and BPM detection
 
 ### Current Analysis Features
 - **RMS Power Analysis**: 10-second rolling window with 2-second hops
 - **Adaptive Color Mapping**: Automatically adjusts scale based on detected headroom
-  - High dynamic range: 0-0.6 scale for loud masters
+  - High dynamic range: 0-0.6 scale for loud masters  
   - Conservative mastering: 0-0.3 scale for quiet masters
 - **BPM Detection**: Automatic tempo analysis
-- **Metadata Display**: Artist and title from ID3 tags
+- **Metadata Display**: Artist and title from audio tags
+- **Real-time Visualization**: Embedded matplotlib plots with font-aware rendering
 
-### Known Issues
-- GUI integration incomplete (drag-drop doesn't trigger analysis)
-- MP3 tag reading temporarily disabled in some parts
-- No interactive features yet implemented
+### GUI Features
+- **File Management**: Drag-and-drop and file dialog for audio selection
+- **Font Control**: Unified font selector with size control and plot regeneration
+- **Analysis Display**: Real-time visualization with metadata panels
+- **Modular Architecture**: Self-contained widgets for easy layout management
 
 ## Future Development Plans
 
-### Short-term Goals
-1. **Complete GUI Integration**
-   - Connect drag-drop functionality to analysis pipeline
-   - Real-time graph display in GUI window
-   - File browser for batch processing
+### Short-term (Urgent)
+1. **Plot Control Widget Cluster**
+   - Move 'Refresh Plot' into dedicated plot/graph widget cluster
+   - Add metric selection widget (choose which analysis to display)
+   - Implement plot style controller (colormap, line vs bar, etc.)
+   - Prepare foundation for mastering comparison features
 
-2. **Enhanced Metrics**
+### Short-term (Not Urgent)
+1. **Enhanced Metrics**
+   - LUFS loudness measurement implementation
    - Dynamic range measurement (DR meter)
    - Peak-to-average ratio analysis
    - Frequency spectrum analysis
-   - Loudness standards compliance (LUFS)
 
-3. **Interactive Features**
-   - Zoom/pan on power graphs
-   - Playback controls with visual cursor
+2. **Interactive Plot Features**
+   - GUI-controllable plotting styles (colormap, visualization type)
+   - Select axis ranges on the fly with automatic graph updates
+   - Zoom/pan controls for detailed analysis
    - Export analysis results to CSV/JSON
 
-### Medium-term Goals
+3. **Advanced GUI Controls**
+   - Plot style customization interface
+   - Real-time axis range selection
+   - Interactive plot manipulation tools
+
+### Mid-Long term (Not Urgent)
+1. **Audio Comparison System**
+   - Reference vs. comparee audio file analysis
+   - Side-by-side track comparison interface
+   - A/B testing for mastering versions
+   - Overlay visualization for comparative analysis
+
+2. **Distribution & Deployment**
+   - Self-contained executable releases
+   - Cross-platform packaging
+   - Installer creation and distribution
+
+### Future Vision
 1. **Advanced Analysis Tools**
    - Spectral centroid and bandwidth analysis
    - Stereo width measurements
    - Transient detection and analysis
    - Harmonic distortion detection
 
-2. **Comparison Features**
-   - Side-by-side track comparison
-   - Reference track overlay
-   - Mastering version A/B testing
-
-3. **Batch Processing**
-   - Folder-based analysis
-   - Automated report generation
-   - Progress tracking for large collections
-
-### Long-term Vision
-1. **VST Plugin Development**
-   - Real-time analysis during mixing/mastering
-   - Integration with DAWs
-   - Live feedback during production
-
 2. **Professional Features**
    - EBU R128 compliance checking
    - Custom target curves
    - Professional reporting formats
    - Multi-format export capabilities
 
+3. **VST Plugin Development**
+   - Real-time analysis during mixing/mastering
+   - Integration with DAWs
+   - Live feedback during production
+
 ## Development Notes
 
 ### Dependencies
@@ -121,12 +143,18 @@ A custom mastering toolkit that provides metrics to evaluate audio masterings th
 ## Usage
 
 ### Current Usage
+1. Run `python main.py` to launch the GUI application
+2. Use "Open Audio File..." button or drag-and-drop audio files for analysis
+3. Adjust font settings using the Font Settings panel
+4. View real-time analysis results with embedded matplotlib plots
+5. Select different analyzed files from the file list to compare results
+
+### Legacy Usage (Batch Mode)
 1. Add audio file paths to `files.txt`
 2. Run `python master_core.py` for batch analysis
-3. Run `python main.py` for GUI (incomplete)
 
-### Planned Usage
-1. Drag and drop audio files into GUI
-2. Real-time analysis with interactive graphs
-3. Export reports and comparisons
-4. VST plugin for DAW integration
\ No newline at end of file
+### Planned Usage Enhancements
+1. Interactive plot manipulation and style customization
+2. LUFS and advanced metric analysis
+3. Audio file comparison features
+4. Self-contained executable releases
\ No newline at end of file
diff --git a/README.md b/README.md
index 82261ed..5246010 100644
--- a/README.md
+++ b/README.md
@@ -1,29 +1,78 @@
 # uj-mastering-master
-Utility providing metrics to evaluate masterings.  
-Now boosted by Claude Code.
+Custom mastering toolkit providing comprehensive metrics to evaluate audio masterings through visual analysis.  
+Developed with Claude Code assistance.
 
-## dependencies
-librosa, numpy, matplotlib, mutagen
+## Features
 
-## usage
+### ✅ Current Implementation
+- **Complete GUI Application**: Modular PyQt5 interface with drag-and-drop and file dialog support
+- **Real-time Analysis**: Background threading with embedded matplotlib visualization
+- **Font Management**: CJK-compatible font system with custom font support from `fonts/` directory
+- **Audio Support**: MP3, WAV, and FLAC file analysis
+- **RMS Power Analysis**: Rolling window analysis with adaptive color mapping
+- **Metadata Display**: Automatic extraction and display of audio tags and BPM
 
-### Command Line Analysis
-1. Edit `files.txt` to include paths to your audio files (MP3/WAV supported)
-   - Use `;` or `#` to comment out files
-   - One file path per line
-2. Run: `python master_core.py`
-   - Generates colorized power magnitude graphs for each file
-   - Displays BPM and song metadata
-   - Graphs show RMS power over time with adaptive scaling
+### 🚧 In Development
+- **Plot Control Widgets**: Dedicated cluster for plot manipulation and style controls
+- **LUFS Metrics**: Professional loudness measurement implementation
+- **Interactive Plotting**: Real-time axis control and style customization
 
-### GUI Mode (Experimental)
-Run: `python main.py`
-- Opens drag-and-drop interface
-- Currently displays dropped file paths
-- Analysis integration coming soon
+### 🔮 Planned Features
+- **Audio Comparison**: Reference vs. comparee analysis for mastering evaluation
+- **Advanced Metrics**: Dynamic range, spectral analysis, and professional standards compliance
+- **Standalone Releases**: Self-contained executable distribution
 
-### Output
-- Interactive matplotlib graphs showing power levels over time
-- Color-coded visualization (autumn colormap)
-- Automatic headroom detection and scaling
-- Console output with BPM and metadata information
\ No newline at end of file
+## Dependencies
+- **Core**: `librosa`, `numpy`, `matplotlib`, `mutagen`
+- **GUI**: `PyQt5`
+- **Audio Processing**: Advanced librosa-based analysis pipeline
+
+## Usage
+
+### GUI Application (Recommended)
+```bash
+python main.py
+```
+- **Load Files**: Use "Open Audio File..." button or drag-and-drop
+- **Font Control**: Adjust interface fonts and regenerate plots automatically  
+- **Analysis Display**: View real-time RMS power analysis with metadata
+- **File Management**: Switch between analyzed files using the file list
+
+### Command Line Analysis (Legacy)
+```bash
+# 1. Edit files.txt with your audio file paths
+# 2. Run batch analysis
+python master_core.py
+```
+
+## Architecture
+
+### Modular Design
+- **Self-contained Widgets**: Easy layout management and customization
+- **Background Processing**: Non-blocking analysis with progress feedback
+- **Signal-based Communication**: Clean separation between GUI and analysis logic
+
+### Key Components
+- `main.py`: Complete GUI application with modular architecture
+- `font_control_widget.py`: Unified font management with plot regeneration
+- `analysis_results_manager.py`: Threaded analysis with caching
+- `audio_visualization_widget.py`: Embedded matplotlib with Qt integration
+
+## Development Roadmap
+
+### 🎯 Next Priority: Plot Control System
+Moving from font-focused interface to comprehensive plot manipulation:
+- Cluster plot controls (refresh, style, metric selection)
+- Interactive axis range selection
+- Real-time plot style customization
+- Foundation for comparison features
+
+### 🎵 Short-term Goals
+- **LUFS Implementation**: Professional loudness standards
+- **Plot Interactivity**: GUI-controlled visualization styles
+- **Metric Selection**: Choose which analysis to display
+
+### 🎼 Long-term Vision
+- **Mastering Comparison**: Side-by-side analysis tools
+- **Professional Standards**: EBU R128 compliance checking
+- **Standalone Distribution**: Self-contained executable releases
\ No newline at end of file