diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0390d480..ff7b5bad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,144 @@ All notable changes to Claude Code Workflow (CCW) will be documented in this fil
The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+## [4.3.0] - 2025-10-10
+
+### ๐จ UI Design Workflow V2 - Self-Contained CSS Architecture
+
+This release introduces a major architectural improvement to the UI Design Workflow, removing the placeholder mechanism and enabling agents to generate fully self-contained CSS files directly from design tokens.
+
+#### Changed
+
+**UI Design Workflow V2 Commands**:
+- **`/workflow:ui-design:generate-v2`**: Enhanced prototype generation with self-contained CSS
+ - Agents now read `design-tokens.json` and generate independent CSS files
+ - CSS contains direct token values (e.g., `#3b82f6`) instead of `var()` references
+ - HTML files reference CSS directly: ``
+ - No more placeholder mechanism or post-processing steps
+
+- **`/workflow:ui-design:explore-auto-v2`**: Updated to use new generation architecture
+ - Automatic coordination with `generate-v2` command
+ - Streamlined workflow without placeholder replacement
+
+**Removed Dependencies**:
+- โ **No more `tokens.css`**: Eliminated intermediate CSS variable files
+- โ **No more Phase 1.6**: Removed token-to-CSS conversion step
+- โ **No more placeholder replacement**: Scripts no longer process `{{STYLE_CSS}}` placeholders
+
+**Agent Instructions Enhanced**:
+- Agents receive `design-tokens.json` as primary design system reference
+- Direct CSS generation instructions with token value extraction guidance
+- Better adaptation to `design_attributes` (density, visual_weight, formality, etc.)
+- Example instruction: "Use color values for backgrounds, typography values for fonts"
+
+**Script Simplification** (`ui-generate-preview-v2.sh`):
+- Removed placeholder replacement logic (32 lines removed)
+- Focus solely on preview file generation (compare.html, index.html, PREVIEW.md)
+- Cleaner, more focused responsibility
+
+#### Improved
+
+**Style Differentiation**:
+- ๐จ **Better Style Diversity**: Agents can now freely adapt token values based on design philosophy
+- ๐ฏ **Stronger Visual Identity**: Each style variant can use different color spaces, typography scales
+- ๐ก **Design-Aware Selection**: Agents intelligently select tokens matching design_attributes
+
+**Workflow Simplicity**:
+- ๐ **Reduced Complexity**: 346 lines of code removed (net reduction)
+- โก **Fewer Steps**: Eliminated intermediate conversion and replacement phases
+- ๐ง **Easier Debugging**: All styling visible directly in generated CSS files
+- ๐ **Clearer Agent Tasks**: Agents have single, focused responsibility
+
+**CSS Generation Quality**:
+- ๐จ **Fully Embodies Design**: CSS directly reflects design token values
+- ๐ **No External Dependencies**: Each CSS file is completely self-contained
+- ๐ **Better Adaptation**: Agents can adjust values based on layout context
+- ๐ฏ **Style-Specific Implementation**: Same layout + different style = truly different CSS
+
+#### Technical Details
+
+**Before (v4.2.x)**:
+```html
+
+
+
+
+
+
+```
+
+**After (v4.3.0)**:
+```html
+
+
+
+
+.button { background: #3b82f6; font-size: 16px; }
+```
+
+**Workflow Comparison**:
+```
+Old Flow:
+Phase 1.5: Inspiration โ Phase 1.6: Token Conversion โ Phase 2: Agent Gen โ
+Phase 3a: Replace Placeholders โ Phase 3b: Preview
+
+New Flow:
+Phase 1.5: Inspiration โ Phase 2: Agent Gen (reads tokens.json directly) โ
+Phase 3: Preview
+```
+
+#### Benefits
+
+**Developer Experience**:
+- ๐ **Faster Execution**: Removed 2 intermediate processing steps
+- ๐ **Simpler Output**: No more tokens.css files to manage
+- ๐ **Easier Inspection**: All styling visible in prototype CSS files
+- ๐ฏ **Clearer Intent**: Direct mapping from design tokens to CSS
+
+**Design Quality**:
+- ๐จ **Richer Style Variations**: Agents can adapt token usage creatively
+- ๐ช **Stronger Differentiation**: Each style truly looks different
+- ๐ฏ **Context-Aware Styling**: Agents adjust tokens based on layout needs
+- โจ **Better Design Expression**: No constraints from CSS variable structure
+
+**Maintainability**:
+- ๐ **Less Code**: 346 lines removed (5 files modified)
+- ๐ง **Fewer Moving Parts**: Removed token conversion and placeholder systems
+- ๐ **Clearer Responsibilities**: Scripts focus on single purpose
+- ๐งช **Easier Testing**: Self-contained files easier to validate
+
+#### Files Changed
+
+**Commands Updated**:
+- `.claude/commands/workflow/ui-design/generate-v2.md`: Removed Phase 1.6 and Phase 3a, updated agent instructions
+- `.claude/commands/workflow/ui-design/explore-auto-v2.md`: Updated to work with new architecture
+- `.claude/commands/workflow/ui-design/generate.md`: Documentation updates
+- `.claude/commands/workflow/ui-design/extract.md`: Documentation updates
+
+**Scripts Modified**:
+- `.claude/scripts/ui-generate-preview-v2.sh`: Removed placeholder replacement (32 lines)
+
+**Total Impact**:
+- 5 files changed
+- 471 insertions, 817 deletions
+- Net: -346 lines (31% reduction in UI generation code)
+
+#### Migration Notes
+
+**No Breaking Changes** for users:
+- โ
V2 commands are separate from V1 (`generate-v2` vs `generate`)
+- โ
Existing workflows continue to work unchanged
+- โ
New commands are opt-in
+
+**For New Projects**:
+- Use `/workflow:ui-design:generate-v2` for better style differentiation
+- Use `/workflow:ui-design:explore-auto-v2` for automatic workflow
+
+**Design Token Changes**:
+- `design-tokens.json` structure unchanged
+- `tokens.css` files no longer generated (V2 commands only)
+- Style guides (`style-guide.md`) unchanged
+
## [4.2.1] - 2025-10-10
### ๐ Command Renaming & Documentation Refactoring