diff --git a/README.rst b/README.rst
index a8c26a0..88bdf8d 100644
--- a/README.rst
+++ b/README.rst
@@ -5,7 +5,7 @@ flagit
 .. image:: https://github.com/TUW-GEO/flagit/actions/workflows/build.yml/badge.svg?branch=main
    :target: https://github.com/TUW-GEO/flagit/actions
 
-.. image:: https://coveralls.io/repos/github/TUW-GEO/flagit/badge.svg?branch=main
+.. image:: https://coveralls.io/repos/github/TUW-GEO/flagit/badge.png?branch=main
     :target: https://coveralls.io/github/TUW-GEO/flagit?branch=main
 
 .. image:: https://badge.fury.io/py/flagit.svg
diff --git a/docs/conf.py b/docs/conf.py
index 60c0666..d8848bf 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -148,7 +148,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'default'
+html_theme = 'sphinx_rtd_theme'
 
 # 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