Admonition not properly styled

[mrelbe1]

The dark theme is really great - many thanks!

However, I have found a problem with general admonitions:

.. admonition:: Title

   This is not a note or warning, just a general admonition with
   some ``monospaced text``. `Link color <#>`_ is fine.

This is rendered as:

I intend to make a PR as a proposal to fix this.