diff --git a/doc/en/conf.py b/doc/en/conf.py
index 43e7fc79e..12daac69c 100644
--- a/doc/en/conf.py
+++ b/doc/en/conf.py
@@ -105,9 +105,12 @@ pygments_style = 'sphinx'
 
 # -- Options for HTML output ---------------------------------------------------
 
+sys.path.append(os.path.abspath('_themes'))
+html_theme_path = ['_themes']
+
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'sphinxdoc'
+html_theme = 'flask'
 
 # 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