Update app.py

app.py

@@ -170,6 +170,11 @@ class FontManager:
         
         return font_paths
 
+class QuizGenerationError(Exception):
+    """Exception raised for errors in quiz generation"""
+    pass
+
+
 class CertificateGenerator:
     def __init__(self):
         self.certificate_size = (1200, 800)
@@ -184,6 +189,7 @@ class CertificateGenerator:
         """Load fonts with fallbacks"""
         fonts = {}
         try:
+            # Use Liberation Sans fonts instead of Arial
             fonts['title'] = ImageFont.truetype(self.font_paths['bold'], 60)
             fonts['text'] = ImageFont.truetype(self.font_paths['regular'], 40)
             fonts['subtitle'] = ImageFont.truetype(self.font_paths['regular'], 30)