diff --git a/learnapp.py b/learnapp.py
index f8e56b6..ddc711d 100644
--- a/learnapp.py
+++ b/learnapp.py
@@ -287,6 +287,7 @@ def build_dependency_graph(config={}):
 
     # iterate over topics and build graph
     topics = config.get('topics', {})
+    tcount = qcount = 0   # topic and question counters
     for ref,attr in topics.items():
         g.add_node(ref)
         tnode = g.node[ref]  # current node (topic)
@@ -313,5 +314,8 @@ def build_dependency_graph(config={}):
                 tnode['factory'][q['ref']] = QFactory(q)
 
         logger.info(f'{len(tnode["questions"]):6} {ref}')
+        qcount += len(tnode["questions"])  # count total questions
+        tcount += 1
 
+    logger.info(f'Total loaded: {tcount} topics, {qcount} questions')
     return g
diff --git a/serve.py b/serve.py
index 78a6984..087bc1a 100755
--- a/serve.py
+++ b/serve.py
@@ -13,7 +13,7 @@ from concurrent.futures import ThreadPoolExecutor
 import tornado.ioloop
 import tornado.web
 import tornado.httpserver
-from tornado import template    #, gen
+from tornado import template, iostream, gen
 
 from tornado.concurrent import run_on_executor
 from tornado.platform.asyncio import to_tornado_future
@@ -101,7 +101,7 @@ class ChangePasswordHandler(BaseHandler):
     @tornado.web.authenticated
     def post(self):
         uid = self.current_user
-        pw = self.get_body_arguments('new_password')[0];
+        pw = self.get_body_arguments('new_password')[0]
 
         if self.learn.change_password(uid, pw):
             notification = tornado.escape.to_unicode(self.render_string('notification.html', type='success', msg='A password foi alterada!'))
@@ -152,12 +152,13 @@ class TopicHandler(BaseHandler):
 # Based on https://bhch.github.io/posts/2017/12/serving-large-files-with-tornado-safely-without-blocking/
 # ----------------------------------------------------------------------------
 class FileHandler(BaseHandler):
+    chunk_size = 4 * 1024 * 1024  # serve up to 4 MiB multiple times
+
     @tornado.web.authenticated
     async def get(self, filename):
         uid = self.current_user
         public_dir = self.learn.get_current_public_dir(uid)
         filepath = path.expanduser(path.join(public_dir, filename))
-        chunk_size = 1024 * 1024 # serve up to 1MiB multiple times
         try:
             f = open(filepath, 'rb')
         except FileNotFoundError:
@@ -166,7 +167,7 @@ class FileHandler(BaseHandler):
             logging.error(f'No permission: {filepath}')
         else:
             with f:
-                chunk = f.read(chunk_size)
+                chunk = f.read(self.chunk_size)
                 while chunk:
                     try:
                         self.write(chunk)   # write the cunk to response
@@ -178,7 +179,7 @@ class FileHandler(BaseHandler):
                         del chunk
                         await gen.sleep(0.000000001) # 1 nanosecond (hack)
                         # in tornnado 5.0 use `await asyncio.sleep(0)` instead
-                    chunk = f.read(chunk_size)
+                    chunk = f.read(self.chunk_size)
 
 
 # ----------------------------------------------------------------------------
@@ -320,12 +321,17 @@ def main():
         raise e
 
     # --- create webserver
-    http_server = tornado.httpserver.HTTPServer(webapp,
-        ssl_options={
-            "certfile": "certs/cert.pem",
-            "keyfile": "certs/privkey.pem"
-        })
-    http_server.listen(8443)
+    try:
+        http_server = tornado.httpserver.HTTPServer(webapp,
+            ssl_options={
+                "certfile": "certs/cert.pem",
+                "keyfile": "certs/privkey.pem"
+            })
+    except ValueError:
+        logging.critical('Certificates cert.pem, privkey.pem not found')
+        sys.exit(1)
+    else:
+        http_server.listen(8443)
 
     # --- run webserver
     logging.info('Webserver running...')
diff --git a/templates/maintopics.html b/templates/maintopics.html
index 023abe9..3bd93d8 100644
--- a/templates/maintopics.html
+++ b/templates/maintopics.html
@@ -98,9 +98,11 @@
         </a>
       {% end %}
     {% end %}
-  </div> <!-- list-group -->
+  </div>
+  <!-- list-group -->
 </div>
 
+
 <!-- === Change Password Modal =========================================== -->
 <div id="password_modal" class="modal fade" tabindex="-1" role="dialog">
   <div class="modal-dialog modal-sm" role="document">
--
libgit2 0.21.2