Add feature description to readme

README.rst

@@ -6,7 +6,20 @@ Sphinx audEERING theme
 
 Sphinx_ theme to style your documentation project with audEERING colors.
 
+The theme extends the official `readthedocs theme`_ by
+
+* audEERING colors and logo
+* support for wide pages, useful for wide tables
+* better formatting of tables
+* custom styling of figure captions
+* make `juptyer-sphinx`_ code cells appear like normal code cells
+* custom styling for `copy-button`_ and nbsphinx_
+
 .. _Sphinx: http://www.sphinx-doc.org/
+.. _readthedocs theme: https://sphinx-rtd-theme.readthedocs.io/
+.. _juptyer-sphinx: https://jupyter-sphinx.readthedocs.io/
+.. _copy-button: https://sphinx-copybutton.readthedocs.io/
+.. _nbsphinx: https://nbsphinx.readthedocs.io/
 
 .. badges images and links:
 .. |tests| image:: https://github.com/audeering/sphinx-audeering-theme/workflows/Test/badge.svg