diff --git a/src/gdiffer/language_detector.py b/src/gdiffer/language_detector.py
index 0d6ad3c..c50200f 100644
--- a/src/gdiffer/language_detector.py
+++ b/src/gdiffer/language_detector.py
@@ -68,75 +68,75 @@ class LanguageDetector:
 
     CONTENT_PATTERNS = {
         'python': [
-            r'^import\s+\w+',
-            r'^from\s+\w+\s+import',
-            r'^def\s+\w+\s*\(',
-            r'^class\s+\w+\s*[:\(]',
-            r'^if\s+__name__\s*==\s*['"]__main__['"]',
+            r'^import\\s+\\w+',
+            r'^from\\s+\\w+\\s+import',
+            r'^def\\s+\\w+\\s*\\(',
+            r'^class\\s+\\w+\\s*[:\\(]',
+            r'^if\\s+__name__\\s*==\\s*[\\'\\"]__main__[\\'\\"]',
         ],
         'javascript': [
-            r'^const\s+\w+\s*=',
-            r'^let\s+\w+\s*=',
-            r'^var\s+\w+\s*=',
-            r'^function\s+\w+\s*\(',
-            r'=>\s*\{',
-            r'import\s+.*\s+from',
-            r'export\s+(default\s+)?',
+            r'^const\\s+\\w+\\s*=',
+            r'^let\\s+\\w+\\s*=',
+            r'^var\\s+\\w+\\s*=',
+            r'^function\\s+\\w+\\s*\\(',
+            r'=>\\s*\\{',
+            r'import\\s+.*\\s+from',
+            r'export\\s+(default\\s+)?',
         ],
         'typescript': [
-            r'^interface\s+\w+\s*\{',
-            r'^type\s+\w+\s*=',
-            r':\s*(string|number|boolean|any|void|null|undefined)',
-            r'<[A-Z]\w*>',
+            r'^interface\\s+\\w+\\s*\\{',
+            r'^type\\s+\\w+\\s*=',
+            r':\\s*(string|number|boolean|any|void|null|undefined)',
+            r'<[A-Z]\\w*>',
         ],
         'java': [
-            r'^package\s+[\w.]+;',
-            r'^import\s+[\w.]+;',
-            r'^public\s+(class|interface|enum)\s+\w+',
-            r'^private\s+(static\s+)?(final\s+)?\w+\s+\w+;',
+            r'^package\\s+[\\w.]+;',
+            r'^import\\s+[\\w.]+;',
+            r'^public\\s+(class|interface|enum)\\s+\\w+',
+            r'^private\\s+(static\\s+)?(final\\s+)?\\w+\\s+\\w+;',
         ],
         'go': [
-            r'^package\s+\w+',
-            r'^import\s*\(',
-            r'func\s+\w+\s*\(',
+            r'^package\\s+\\w+',
+            r'^import\\s+\\(',
+            r'func\\s+\\w+\\s*\\(',
             r':=',
-            r'go\s+func',
+            r'go\\s+func',
         ],
         'rust': [
-            r'^fn\s+\w+\s*\(',
-            r'^impl\s+\w+',
-            r'^struct\s+\w+',
-            r'^enum\s+\w+',
-            r'let\s+mut\s+\w+',
-            r'->\s*\w+',
+            r'^fn\\s+\\w+\\s*\\(',
+            r'^impl\\s+\\w+',
+            r'^struct\\s+\\w+',
+            r'^enum\\s+\\w+',
+            r'let\\s+mut\\s+\\w+',
+            r'->\\s*\\w+',
         ],
         'c': [
-            r'#include\s*<',
-            r'#include\s*"',
-            r'int\s+main\s*\(',
-            r'struct\s+\w+\s*\{',
-            r'void\s+\?\s*\w+\s*\(',
+            r'#include\\s*<',
+            r'#include\\s*"',
+            r'int\\s+main\\s*\\(',
+            r'struct\\s+\\w+\\s*\\{',
+            r'void\\s+\\*?\\s*\\w+\\s*\\(',
         ],
         'cpp': [
-            r'#include\s*<',
-            r'#include\s*"',
-            r'class\s+\w+\s*(:\s*public)?',
-            r'std::\w+',
-            r'using\s+namespace\s+std',
+            r'#include\\s*<',
+            r'#include\\s*"',
+            r'class\\s+\\w+\\s*(:\\s*public)?',
+            r'std::\\w+',
+            r'using\\s+namespace\\s+std',
         ],
         'ruby': [
-            r'^require\s+['"]',
-            r'^class\s+\w+(\s*<\s*\w+)?',
-            r'^module\s+\w+',
-            r'def\s+\w+',
-            r'puts\s+',
+            r'^require\\s+[\\'\\"]',
+            r'^class\\s+\\w+(\\s*<\\s*\\w+)?',
+            r'^module\\s+\\w+',
+            r'def\\s+\\w+',
+            r'puts\\s+',
             r'puts!',
         ],
         'php': [
-            r'\<\?php',
-            r'\$\w+\s*=',
-            r'function\s+\w+\s*\(',
-            r'class\s+\w+\s*\{',
+            r'<\\?php',
+            r'\\$\\w+\\s*=',
+            r'function\\s+\\w+\\s*\\(',
+            r'class\\s+\\w+\\s*\\{',
         ],
     }
 
@@ -153,7 +153,7 @@ class LanguageDetector:
 
     def detect_from_content(self, content: str) -> str | None:
         """Detect language from file content patterns."""
-        first_lines = '\n'.join(content.splitlines()[:50])
+        first_lines = '\\n'.join(content.splitlines()[:50])
 
         scores: dict[str, int] = {}
 
@@ -177,7 +177,9 @@ class LanguageDetector:
         """Detect language from filename and optionally content."""
         ext_lang = self.detect_from_filename(filename)
 
-        if ext_lang and ext_lang not in ['text', 'markdown', 'json', 'yaml', 'xml', 'html', 'css', 'dockerfile']:
+        if ext_lang and ext_lang not in [
+            'text', 'markdown', 'json', 'yaml', 'xml', 'html', 'css', 'dockerfile'
+        ]:
             if content:
                 content_lang = self.detect_from_content(content)
                 if content_lang and content_lang != ext_lang: