feat: implement scroll indicators with disabled state styling

- Add document viewport scroll indicators with triangular arrows
- Implement disabled state styling (grey background, cursor: not-allowed)
- Add smooth scrolling with easing functions for indicator clicks
- Include hover detection at top/bottom of viewport for indicator display
- Fix CSS syntax error in scroll indicator styles
- Add theme-aware styling for all UI themes (standard, greyscale, electric, psychedelic)
- Extend confirmation dialog with theme-consistent danger and secondary button properties
- Update UserInterfaceFramework.md to mark confirmation dialog as completed

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

UserInterfaceFramework.md

@@ -208,23 +208,43 @@ Provides detailed information about the current editing session, including versi
 ### Description
 Provides user confirmation for potentially destructive operations that cannot be easily undone.
 
-### Current Implementation
-- **Method**: Browser native `confirm()` (temporary solution)
+### Current Implementation ✅ COMPLETED
+- **Method**: Custom theme-aware modal dialog
 - **Trigger**: "🔄 Reset All" button in floating action panel
-- **Message**: "Reset all content to original markdown? This will lose all edits and remove split sections."
+- **Message**: "Reset all content to original markdown?"
+- **Warning**: "This will permanently lose all edits and remove any split sections. This action cannot be undone."
+
+### Features Implemented
+- **Theme-Aware Styling**: Adapts to all UI themes (standard, greyscale, electric, psychedelic)
+- **Clear Action Buttons**:
+  - Primary action: "Reset Document" (red danger button)
+  - Secondary action: "Keep Changes" (grey cancel button)
+- **Enhanced UX**:
+  - Detailed consequence explanation with warning styling
+  - Professional modal overlay with smooth animations
+  - Proper focus management and accessibility
+- **Keyboard Support**:
+  - ESC key to cancel
+  - Enter key to confirm
+  - Tab navigation between buttons
 
 ### Use Cases
 - **Reset All Sections**: Complete document reset to original state
-- **Future**: Delete operations, bulk changes, file operations
+- **Future**: Extensible for delete operations, bulk changes, file operations
 
-### Future Enhancement Plan
-**Target**: Replace browser confirm with custom modal dialog
-- **Styling**: Theme-aware modal with clear action buttons
-- **Features**:
-  - Clear primary/secondary action buttons
-  - Detailed consequence explanation
-  - Optional "Don't ask again" for non-critical confirmations
-- **Accessibility**: Proper focus management, keyboard support
+### Technical Implementation
+**CSS Classes**:
+- `.ui-edit-confirmation-modal` - Modal container
+- `.ui-edit-confirmation-content` - Main message
+- `.ui-edit-confirmation-warning` - Warning section
+- `.ui-edit-confirmation-buttons` - Button container
+- `.ui-edit-button-confirm` - Danger action button
+- `.ui-edit-button-cancel` - Cancel action button
+
+**JavaScript Method**: `showConfirmation(message, confirmText, cancelText, warningText)`
+- Returns Promise<boolean> for async/await support
+- Theme-consistent styling via layered theme system
+- Proper event cleanup and accessibility features
 
 ---