diff --git a/loglens/analyzers/analyzer.py b/loglens/analyzers/analyzer.py
index 1a1368f..d40dac1 100644
--- a/loglens/analyzers/analyzer.py
+++ b/loglens/analyzers/analyzer.py
@@ -1,20 +1,21 @@
-"""Log analyzer orchestrator."""
+'''Log analyzer orchestrator.'''
 
-from collections import Counter, defaultdict
+from collections import Counter
 from dataclasses import dataclass, field
 from datetime import datetime
-from typing import Any, Dict, List, Optional
+from typing import Any, Optional
 
+from loglens.analyzers.patterns import PatternLibrary
+from loglens.analyzers.severity import SeverityClassifier
 from loglens.parsers.base import LogFormat, ParsedLogEntry
 from loglens.parsers.factory import ParserFactory
-from loglens.analyzers.patterns import ErrorPattern, PatternLibrary
-from loglens.analyzers.severity import SeverityClassifier, SeverityLevel
 
 
 @dataclass
 class AnalysisResult:
-    """Result of log analysis."""
-    entries: List[ParsedLogEntry] = field(default_factory=list)
+    '''Result of log analysis.'''
+
+    entries: list[ParsedLogEntry] = field(default_factory=list)
     format_detected: LogFormat = LogFormat.UNKNOWN
     total_lines: int = 0
     parsed_count: int = 0
@@ -22,19 +23,19 @@ class AnalysisResult:
     warning_count: int = 0
     critical_count: int = 0
     debug_count: int = 0
-    pattern_matches: Dict[str, int] = field(default_factory=dict)
-    severity_breakdown: Dict[str, int] = field(default_factory=dict)
-    top_errors: List[Dict[str, Any]] = field(default_factory=list)
-    host_breakdown: Dict[str, int] = field(default_factory=dict)
+    pattern_matches: dict[str, int] = field(default_factory=dict)
+    severity_breakdown: dict[str, int] = field(default_factory=dict)
+    top_errors: list[dict[str, Any]] = field(default_factory=list)
+    host_breakdown: dict[str, int] = field(default_factory=dict)
     time_range: Optional[tuple] = None
     analysis_time: datetime = field(default_factory=datetime.now)
-    suggestions: List[str] = field(default_factory=list)
+    suggestions: list[str] = field(default_factory=list)
 
 
 class LogAnalyzer:
-    """Orchestrates log parsing and analysis."""
+    '''Orchestrates log parsing and analysis.'''
 
-    def __init__(self, config: Optional[Dict[str, Any]] = None):
+    def __init__(self, config: Optional[dict[str, Any]] = None):
         self.parser_factory = ParserFactory()
         self.pattern_library = PatternLibrary()
         self.severity_classifier = SeverityClassifier(
@@ -42,12 +43,9 @@ class LogAnalyzer:
         )
         self.config = config or {}
 
-    def analyze(self, lines: List[str], format: Optional[LogFormat] = None) -> AnalysisResult:
-        """Analyze a list of log lines."""
-        result = AnalysisResult(
-            total_lines=len(lines),
-            analysis_time=datetime.now()
-        )
+    def analyze(self, lines: list[str], format: Optional[LogFormat] = None) -> AnalysisResult:
+        '''Analyze a list of log lines.'''
+        result = AnalysisResult(total_lines=len(lines), analysis_time=datetime.now())
 
         if not lines:
             return result
@@ -69,7 +67,7 @@ class LogAnalyzer:
         return result
 
     def _analyze_entry(self, entry: ParsedLogEntry) -> None:
-        """Analyze a single entry."""
+        '''Analyze a single entry.'''
         message = entry.message or ""
         raw_text = entry.raw_line
 
@@ -79,14 +77,12 @@ class LogAnalyzer:
             entry.error_pattern = pattern.name
 
         severity = self.severity_classifier.classify(
-            level=entry.level,
-            message=message,
-            pattern_match=entry.error_pattern
+            level=entry.level, message=message, pattern_match=entry.error_pattern
         )
         entry.severity = severity.value
 
     def _compute_statistics(self, result: AnalysisResult) -> None:
-        """Compute statistics from analyzed entries."""
+        '''Compute statistics from analyzed entries.'''
         severity_counts = Counter()
         pattern_counts = Counter()
         host_counts = Counter()
@@ -118,14 +114,13 @@ class LogAnalyzer:
             result.time_range = (min(timestamps), max(timestamps))
 
         result.top_errors = [
-            {"pattern": name, "count": count}
-            for name, count in pattern_counts.most_common(10)
+            {"pattern": name, "count": count} for name, count in pattern_counts.most_common(10)
         ]
 
         result.suggestions = self._generate_suggestions(result)
 
-    def _generate_suggestions(self, result: AnalysisResult) -> List[str]:
-        """Generate suggestions based on analysis."""
+    def _generate_suggestions(self, result: AnalysisResult) -> list[str]:
+        '''Generate suggestions based on analysis.'''
         suggestions = []
 
         if result.critical_count > 0:
@@ -159,20 +154,21 @@ class LogAnalyzer:
         return suggestions
 
     def analyze_file(self, file_path: str, format: Optional[LogFormat] = None) -> AnalysisResult:
-        """Analyze a log file."""
-        with open(file_path, 'r', encoding='utf-8', errors='replace') as f:
+        '''Analyze a log file.'''
+        with open(file_path, encoding="utf-8", errors="replace") as f:
             lines = f.readlines()
 
         return self.analyze(lines, format)
 
     def analyze_stdin(self) -> AnalysisResult:
-        """Analyze from stdin."""
+        '''Analyze from stdin.'''
         import sys
+
         lines = sys.stdin.readlines()
         return self.analyze(lines)
 
-    def get_pattern_info(self, pattern_name: str) -> Optional[Dict[str, Any]]:
-        """Get information about a pattern."""
+    def get_pattern_info(self, pattern_name: str) -> Optional[dict[str, Any]]:
+        '''Get information about a pattern.'''
         for pattern in self.pattern_library.list_patterns():
             if pattern.name == pattern_name:
                 return {
@@ -182,20 +178,16 @@ class LogAnalyzer:
                     "description": pattern.description,
                     "suggestion": pattern.suggestion,
                     "group": pattern.group,
-                    "enabled": pattern.enabled
+                    "enabled": pattern.enabled,
                 }
         return None
 
-    def list_patterns_by_group(self) -> Dict[str, List[Dict[str, Any]]]:
-        """List all patterns organized by group."""
+    def list_patterns_by_group(self) -> dict[str, list[dict[str, Any]]]:
+        '''List all patterns organized by group.'''
         result = {}
         for group_name, patterns in self.pattern_library.list_groups().items():
             result[group_name] = [
-                {
-                    "name": p.name,
-                    "severity": p.severity,
-                    "description": p.description
-                }
+                {"name": p.name, "severity": p.severity, "description": p.description}
                 for p in patterns
             ]
         return result