Release v2.1.0: Theme System

- Add complete theme infrastructure with 6 pre-built themes
- Add technical architecture example with PlantUML integration
- Implement theme customization capabilities
- Add comprehensive documentation and release notes

Author: mmonterroca

04_tech_architecture

@@ -0,0 +1,271 @@
+# Release Notes - v2.1.0
+
+## 🎨 go-docx v2.1.0 - Themes & Advanced Styling
+
+**Release Date**: October 31, 2025
+
+We're excited to announce **v2.1.0**, bringing powerful **theme support** and **advanced styling capabilities** to go-docx!
+
+---
+
+## 🆕 What's New
+
+### 🎨 Theme System
+
+Complete theme infrastructure for consistent document styling:
+
+- ✅ **Pre-built Themes** - 6 professional themes ready to use
+- ✅ **Theme Colors** - Comprehensive color palettes (Primary, Secondary, Accent, Background, Text, etc.)
+- ✅ **Theme Fonts** - Font families for body, headings, and monospace
+- ✅ **Theme Spacing** - Configurable spacing for paragraphs, headings, and sections
+- ✅ **Custom Themes** - Clone and customize existing themes or create from scratch
+- ✅ **Theme Application** - Apply themes globally to documents with one method call
+
+**Available Themes:**
+
+| Theme | Description | Best For |
+|-------|-------------|----------|
+| `DefaultTheme` | Classic professional look | Business documents, reports |
+| `ModernLight` | Clean, contemporary design | Marketing materials, proposals |
+| `TechPresentation` | Tech-focused with blue accents | Technical documentation, specs |
+| `TechDarkMode` | Dark theme for technical docs | Developer documentation, coding guides |
+| `AcademicFormal` | Traditional academic styling | Research papers, academic reports |
+| `MinimalistClean` | Minimal, distraction-free | Focus documents, minimalist designs |
+
+**Example: Using Themes**
+
+```go
+package main
+
+import (
+    "log"
+    docx "github.com/mmonterroca/docxgo"
+    "github.com/mmonterroca/docxgo/domain"
+    "github.com/mmonterroca/docxgo/themes"
+)
+
+func main() {
+    // Create document with theme
+    doc := docx.NewDocument()
+    themes.TechPresentation.ApplyTo(doc)
+    
+    // Get theme colors and fonts
+    colors := themes.TechPresentation.Colors()
+    fonts := themes.TechPresentation.Fonts()
+    
+    // Use theme settings
+    title, _ := doc.AddParagraph()
+    title.SetStyle(domain.StyleIDHeading1)
+    titleRun, _ := title.AddRun()
+    titleRun.AddText("Technical Architecture Document")
+    
+    body, _ := doc.AddParagraph()
+    bodyRun, _ := body.AddRun()
+    bodyRun.AddText("This document uses the Tech Presentation theme")
+    bodyRun.SetFont(domain.Font{Name: fonts.Body})
+    bodyRun.SetColor(colors.Text)
+    
+    if err := doc.SaveAs("themed.docx"); err != nil {
+        log.Fatal(err)
+    }
+}
+```
+
+**Example: Custom Theme**
+
+```go
+// Clone and customize existing theme
+customTheme := themes.ModernLight.Clone()
+customColors := themes.ThemeColors{
+    Primary:    domain.Color{R: 200, G: 50, B: 50},  // Custom red
+    Secondary:  domain.Color{R: 50, G: 50, B: 200},  // Custom blue
+    Background: domain.Color{R: 255, G: 255, B: 255},
+    Text:       domain.Color{R: 33, G: 33, B: 33},
+    // ... other colors
+}
+customTheme = customTheme.WithColors(customColors)
+customTheme.ApplyTo(doc)
+```
+
+### 📐 Advanced Examples
+
+#### Example 13: Technical Architecture Documents
+
+New comprehensive example demonstrating:
+- Theme application (Light & Dark modes)
+- PlantUML diagram integration
+- Code blocks with syntax highlighting
+- Professional tables with tech styling
+- Architecture decision records
+- Multiple sections with consistent branding
+
+See [`examples/13_themes/04_tech_architecture/`](examples/13_themes/04_tech_architecture/) for complete implementation.
+
+**Features:**
+- Generates both light and dark mode versions
+- Integrates with PlantUML server for UML diagrams (Class, Sequence, Component)
+- Styled code blocks with language indicators
+- Technology comparison tables
+- Cover page with metadata
+- Headers and footers with theme colors
+
+---
+
+## 🔧 Improvements
+
+### Style Management
+- Enhanced built-in style library (40+ styles)
+- Improved style inheritance and customization
+- Better style serialization and persistence
+
+### Error Handling
+- More descriptive error messages for theme operations
+- Validation of theme color values
+- Clear feedback on theme application failures
+
+### Documentation
+- Complete theme system documentation
+- New example showcasing all theme capabilities
+- Updated API documentation with theme methods
+
+---
+
+## 📦 Installation
+
+```bash
+go get github.com/mmonterroca/docxgo@v2.1.0
+```
+
+---
+
+## 🚀 Migration from v2.0.0
+
+v2.1.0 is **fully backward compatible** with v2.0.0. No breaking changes.
+
+### New APIs Added
+
+```go
+// Theme package
+import "github.com/mmonterroca/docxgo/themes"
+
+// Pre-built themes
+themes.DefaultTheme
+themes.ModernLight
+themes.TechPresentation
+themes.TechDarkMode
+themes.AcademicFormal
+themes.MinimalistClean
+
+// Theme application
+theme.ApplyTo(doc)
+
+// Theme properties
+colors := theme.Colors()
+fonts := theme.Fonts()
+spacing := theme.Spacing()
+
+// Customization
+customTheme := theme.Clone()
+customTheme = theme.WithColors(newColors)
+customTheme = theme.WithFonts(newFonts)
+customTheme = theme.WithSpacing(newSpacing)
+```
+
+---
+
+## 🐛 Bug Fixes
+
+- Fixed style preservation when applying themes
+- Corrected font inheritance in themed documents
+- Improved color serialization in OOXML
+- Fixed spacing inconsistencies in themed headings
+
+---
+
+## 📊 Examples
+
+All examples from v2.0.0 continue to work, plus:
+
+| Example | Description | Key Features |
+|---------|-------------|--------------|
+| `13_themes/04_tech_architecture` | Technical documentation | Themes, PlantUML, code blocks, tables |
+
+### Running the New Example
+
+```bash
+cd examples/13_themes/04_tech_architecture
+go run main.go
+```
+
+Generates:
+- `tech_architecture_light.docx` - Light mode technical document
+- `tech_architecture_dark.docx` - Dark mode technical document
+
+---
+
+## 🔗 Compatibility
+
+- **Go Version**: 1.23+
+- **OOXML**: Office Open XML (ISO/IEC 29500)
+- **Microsoft Word**: 2007+ (Windows/Mac)
+- **LibreOffice**: 6.0+ (all platforms)
+- **Google Docs**: Full compatibility
+- **Operating Systems**: Linux, macOS, Windows
+
+---
+
+## 📚 Documentation
+
+### New Documentation
+- **[themes/README.md](themes/README.md)** - Complete theme system guide
+- **[examples/13_themes/README.md](examples/13_themes/README.md)** - Theme example documentation
+
+### Updated Documentation
+- **[README.md](README.md)** - Added theme examples
+- **[docs/V2_API_GUIDE.md](docs/V2_API_GUIDE.md)** - Theme API reference
+
+---
+
+## 🗺️ Roadmap
+
+### v2.2.0 (Q1 2026) - Enhanced Reading
+- Complete Phase 10 (Document Reading to 100%)
+- Read headers/footers from existing documents
+- Read images and complex tables
+- Comments and change tracking
+
+### v2.3.0 (Q2 2026) - Advanced Content
+- Custom XML parts
+- Advanced drawing shapes
+- Enhanced image manipulation
+- Content controls
+
+See [docs/IMPLEMENTATION_STATUS.md](docs/IMPLEMENTATION_STATUS.md) for detailed roadmap.
+
+---
+
+## 🙏 Credits
+
+**v2.1.0 Theme System**: [@mmonterroca](https://github.com/mmonterroca)
+
+**Contributors**: See [CONTRIBUTORS](CONTRIBUTORS) file
+
+---
+
+## 📄 License
+
+**MIT License** - See [LICENSE](LICENSE) file for details.
+
+---
+
+## 🎉 Thank You!
+
+Thank you for using go-docx v2.1.0! We're excited to see the beautiful themed documents you create.
+
+If you find this library useful, please:
+- ⭐ Star the repository on GitHub
+- 📣 Share with your colleagues
+- 🐛 Report issues you encounter
+- 💡 Suggest features you'd like to see
+
+Happy theming! 🎨

RELEASE_NOTES_v2.1.0.md

@@ -197,6 +197,11 @@ func NewDocumentBuilder(opts ...Option) *DocumentBuilder {
 	// Create document with configuration
 	doc := NewDocument()
 
+	builder := &DocumentBuilder{
+		doc:    doc,
+		errors: make([]error, 0),
+	}
+
 	// Apply configuration to document
 	if config.Metadata != nil {
 		if err := doc.SetMetadata(config.Metadata); err != nil {
@@ -206,10 +211,20 @@ func NewDocumentBuilder(opts ...Option) *DocumentBuilder {
 		}
 	}
 
-	return &DocumentBuilder{
-		doc:    doc,
-		errors: make([]error, 0),
+	// Apply theme if provided
+	if config.Theme != nil {
+		// Use type assertion to get Theme interface
+		// This avoids import cycle between docx and themes packages
+		if theme, ok := config.Theme.(interface {
+			ApplyTo(domain.Document) error
+		}); ok {
+			if err := theme.ApplyTo(doc); err != nil {
+				builder.errors = append(builder.errors, err)
+			}
+		}
 	}
+
+	return builder
 }
 
 // AddParagraph adds a new paragraph to the document and returns a ParagraphBuilder.