[fix] default sphinx theme has changed of name

doc/conf.py

@@ -85,7 +85,7 @@ todo_include_todos = True
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'default'
+html_theme = 'classic'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
@@ -105,11 +105,11 @@ html_static_path = ['_static']
 # refs: http://alabaster.readthedocs.io/en/latest/installation.html#sidebars
 html_sidebars = {
     '**': [
-        'about.html',
-        'navigation.html',
-        'relations.html',  # needs 'show_related': True theme option to display
+        # 'about.html',
+        # 'navigation.html',
+        # 'relations.html',  # needs 'show_related': True theme option to display
         'searchbox.html',
-        'donate.html',
+        # 'donate.html',
     ]
 }