Use sphinx_rtd_theme building docs locally

docs/conf.py

@@ -111,18 +111,18 @@ todo_include_todos = False
 
 # -- Options for HTML output ----------------------------------------------
 
-# The theme to use for HTML and HTML Help pages.  See the documentation for
-# a list of builtin themes.
-html_theme = 'default'
+# The theme to use for HTML and HTML Help pages.
+# https://read-the-docs.readthedocs.org/en/latest/theme.html#how-do-i-use-this-locally-and-on-read-the-docs
+if 'READTHEDOCS' not in os.environ:
+    import sphinx_rtd_theme
+    html_theme = 'sphinx_rtd_theme'
+    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # 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
 # documentation.
 #html_theme_options = {}
 
-# Add any paths that contain custom themes here, relative to this directory.
-#html_theme_path = []
-
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
 #html_title = None