fix: improve dark theme link colors for better readability

- Enhanced dark theme with brighter link colors (#79c0ff, #a5d6ff)
- Added corresponding light theme link colors (#0969da, #0550ae)
- Fixed template parsing bug where 'light' theme was falling back to 'basic'
- All theme system tests continue to pass

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

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

markitect/clean_document_manager.py

@@ -134,8 +134,8 @@ class CleanDocumentManager:
         else:
             # Legacy single theme or fallback
             if not template or template not in TEMPLATE_STYLES:
-                # Use default layered themes
-                theme_list = parse_theme_string('basic')
+                # Use default layered themes or the specified theme
+                theme_list = parse_theme_string(template or 'basic')
                 combined_props = combine_theme_properties(theme_list)
                 return self._generate_layered_css(combined_props)
             else:
@@ -267,9 +267,28 @@ class CleanDocumentManager:
                 font-weight: 600;
             }}"""
 
-        # Branding accents (if specified)
+        # Link styling
+        link_css = ""
+        if props.get('link_color'):
+            link_css = f"""
+            a {{
+                color: {props['link_color']};
+                text-decoration: underline;
+            }}"""
+            if props.get('link_hover_color'):
+                link_css += f"""
+            a:hover {{
+                color: {props['link_hover_color']};
+            }}"""
+            else:
+                link_css += """
+            a:hover {
+                opacity: 0.8;
+            }"""
+
+        # Branding accents (if specified and no link_color already set)
         accent_css = ""
-        if props.get('accent_color'):
+        if props.get('accent_color') and not props.get('link_color'):
             accent_css = f"""
             a {{
                 color: {props['accent_color']};
@@ -278,7 +297,7 @@ class CleanDocumentManager:
                 opacity: 0.8;
             }}"""
 
-        return f"<style>{base_css}{heading_css}{text_css}{element_css}{accent_css}</style>"
+        return f"<style>{base_css}{heading_css}{text_css}{element_css}{link_css}{accent_css}</style>"
 
     def _get_legacy_template_css(self, template: str) -> str:
         """Legacy CSS generation - kept for backward compatibility."""