diff --git a/app.py b/app.py
index c02042a97bb..6e25f24e248 100644
--- a/app.py
+++ b/app.py
@@ -2648,10 +2648,20 @@ def split_at(n, xs):
 
 
 if __name__ == '__main__':
+    is_offline = getattr(sys, 'frozen', False) and hasattr(sys, '_MEIPASS')
+
+    if is_offline:
+        # We are running in a standalone build made using pyinstaller.
+        # cd to the directory that has the data files, disable debug mode, and
+        # use port 80 (unless overridden)
+        os.chdir(sys._MEIPASS)
+        config['port'] = int(os.environ.get('PORT', 80))
+
     # Start the server on a developer machine. Flask is initialized in DEBUG mode, so it
     # hot-reloads files. We also flip our own internal "debug mode" flag to True, so our
     # own file loading routines also hot-reload.
-    utils.set_debug_mode(not os.getenv('NO_DEBUG_MODE'))
+    no_debug_mode_requested = os.getenv('NO_DEBUG_MODE')
+    utils.set_debug_mode(not no_debug_mode_requested)
 
     # Set some default environment variables for development mode
     env_defaults = dict(
@@ -2662,12 +2672,9 @@ def split_at(n, xs):
         if key not in os.environ:
             os.environ[key] = value
 
-    if getattr(sys, 'frozen', False) and hasattr(sys, '_MEIPASS'):
-        # We are running via PyInstaller. Cd to the directory that has the data files.
-        os.chdir(sys._MEIPASS)
-
-    # For local debugging, fetch all static files on every request
-    app.config['SEND_FILE_MAX_AGE_DEFAULT'] = None
+    if not is_offline:
+        # For local debugging, fetch all static files on every request
+        app.config['SEND_FILE_MAX_AGE_DEFAULT'] = None
 
     # If we are running in a Python debugger, don't use flasks reload mode. It creates
     # subprocesses which make debugging harder.
@@ -2682,9 +2689,12 @@ def split_at(n, xs):
         start_snapshot = tracemalloc.take_snapshot()
 
     on_server_start()
-    logger.debug('app starting in debug mode')
+    debug = not (is_in_debugger or profile_memory or is_offline)
+    if debug:
+        logger.debug('app starting in debug mode')
+
     # Threaded option enables multiple instances for multiple user access support
-    app.run(threaded=True, debug=not is_in_debugger and not profile_memory,
+    app.run(threaded=True, debug=debug,
             port=config['port'], host="0.0.0.0")
 
     # See `Procfile` for how the server is started on Heroku.
diff --git a/dodo.py b/dodo.py
index 244ca05b4f9..fac49c560fd 100644
--- a/dodo.py
+++ b/dodo.py
@@ -386,7 +386,7 @@ def task__offline():
             'cp data-for-testing.json dist/offlinehedy/_internal/dev_database.json',
             # There are some research papers in the distribution that take up a lot
             # of space.
-            'rm -rf dist/offlinehedy/_internal/content/research',
+            'rm -rf dist/offlinehedy/_internal/content/research/*',
         ],
     )
 
diff --git a/hedy_content.py b/hedy_content.py
index 8e5085c345d..e8be890688e 100644
--- a/hedy_content.py
+++ b/hedy_content.py
@@ -1,5 +1,6 @@
 import logging
 import os
+from os import path
 
 import static_babel_content
 
@@ -392,9 +393,11 @@
     ]
 }
 
+content_dir = path.join(path.dirname(__file__), 'content')
+translations_dir = path.join(path.dirname(__file__), 'translations')
 
 RESEARCH = {}
-for paper in sorted(os.listdir('content/research'),
+for paper in sorted(os.listdir(f'{content_dir}/research'),
                     key=lambda x: int(x.split("_")[-1][:-4]),
                     reverse=True):
     # An_approach_to_describing_the_semantics_of_Hedy_2022.pdf -> 2022, An
@@ -403,16 +406,18 @@
     name = name[-4:] + ". " + name[:-5]
     RESEARCH[name] = paper
 
+
+
 # load all available languages in dict
 # list_translations of babel does about the same, but without territories.
 languages = {}
-if not os.path.isdir('translations'):
+if not os.path.isdir(translations_dir):
     # should not be possible, but if it's moved someday, EN would still be working.
     ALL_LANGUAGES['en'] = 'English'
     ALL_KEYWORD_LANGUAGES['en'] = 'EN'
 
-for folder in os.listdir('translations'):
-    locale_dir = os.path.join('translations', folder, 'LC_MESSAGES')
+for folder in os.listdir(translations_dir):
+    locale_dir = os.path.join(translations_dir, folder, 'LC_MESSAGES')
     if not os.path.isdir(locale_dir):
         continue
     if filter(lambda x: x.endswith('.mo'), os.listdir(locale_dir)):
diff --git a/utils.py b/utils.py
index d77ed3e81a0..b21c88a9a0f 100644
--- a/utils.py
+++ b/utils.py
@@ -6,6 +6,7 @@
 import time
 import functools
 import os
+from os import path
 import re
 import string
 import random
@@ -23,21 +24,23 @@
 
 IS_WINDOWS = os.name == 'nt'
 
+prefixes_dir = path.join(path.dirname(__file__), 'prefixes')
+
 # Define code that will be used if some turtle command is present
-with open('prefixes/turtle.py', encoding='utf-8') as f:
+with open(f'{prefixes_dir}/turtle.py', encoding='utf-8') as f:
     TURTLE_PREFIX_CODE = f.read()
 
 # Preamble that will be used for non-Turtle programs
 # numerals list generated from: https://replit.com/@mevrHermans/multilangnumerals
-with open('prefixes/normal.py', encoding='utf-8') as f:
+with open(f'{prefixes_dir}/normal.py', encoding='utf-8') as f:
     NORMAL_PREFIX_CODE = f.read()
 
 # Define code that will be used if a pressed command is used
-with open('prefixes/pygame.py', encoding='utf-8') as f:
+with open(f'{prefixes_dir}/pygame.py', encoding='utf-8') as f:
     PYGAME_PREFIX_CODE = f.read()
 
 # Define code that will be used if music code is used
-with open('prefixes/music.py', encoding='utf-8') as f:
+with open(f'{prefixes_dir}/music.py', encoding='utf-8') as f:
     MUSIC_PREFIX_CODE = f.read()