app/__init__.py

@@ -35,7 +35,11 @@ def create_app(
     """Create and configure the Flask application."""
     config = AppConfig.from_env(test_config)
 
+    if getattr(sys, "frozen", False):
+        project_root = Path(sys._MEIPASS)
+    else:
         project_root = Path(__file__).resolve().parent.parent
+
     app = Flask(
         __name__,
         static_folder=str(project_root / "static"),

app/config.py

@@ -4,11 +4,17 @@ from __future__ import annotations
 import os
 import secrets
 import shutil
+import sys
 import warnings
 from dataclasses import dataclass
 from pathlib import Path
 from typing import Any, Dict, Optional
 
+if getattr(sys, "frozen", False):
+    # Running in a PyInstaller bundle
+    PROJECT_ROOT = Path(sys._MEIPASS)
+else:
+    # Running in a normal Python environment
     PROJECT_ROOT = Path(__file__).resolve().parent.parent