Release v2.1.0: UI Enhancements & Comprehensive Format Support

🎨 UI/UX Improvements:
- Subtle & small preview popout button with minimalist design
- Simplified table headers with light gray background
- Better readability and cleaner appearance

📥 Enhanced Import:
- Support for 30+ formats: RST, Textile, MediaWiki, Org-mode, AsciiDoc, CSV, JSON, and more
- Format-specific conversion optimizations
- Improved error messages

🎨 Exhaustive ASCII Art Generator:
- 5 text banner styles: Standard, Banner, Block, Bubble, Digital
- 19 professional templates organized in 4 categories
- Flowcharts, sequence diagrams, network diagrams, hierarchy trees
- Note boxes, warning boxes, decorative elements

📝 Documentation:
- Added UPDATES.md with comprehensive changelog
- Updated version to 2.1.0 in all files

🤖 Generated with Claude Code (https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/styles.css

@@ -194,18 +194,19 @@ body {
 
 .preview-popout-btn {
     background: transparent;
-    border: 1px solid #d0d7de;
-    border-radius: 4px;
-    padding: 4px 8px;
+    border: none;
+    border-radius: 3px;
+    padding: 2px 6px;
     cursor: pointer;
-    font-size: 14px;
-    color: #57606a;
+    font-size: 11px;
+    color: #8c959f;
+    opacity: 0.5;
     transition: all 0.2s;
 }
 
 .preview-popout-btn:hover {
-    background: #f3f4f6;
-    border-color: #8c959f;
+    background: rgba(0, 0, 0, 0.05);
+    opacity: 1;
     color: #24292f;
 }