Currently the 3.12 docs are built with Sphinx 4.5.0 (it's shown in the page footer) and 3.13 with Sphinx 6.2.0.

Compare these pages in dark mode:

• https://docs.python.org/3.12/library/asyncio-task.html
• https://docs.python.org/3.13/library/asyncio-task.html

Python 3.12 / Sphinx 4.5.0	Python 3.13 / Sphinx 6.2.0

Looks fine in light mode:

Python 3.12 / Sphinx 4.5.0	Python 3.13 / Sphinx 6.2.0

Previously, we had this CSS from pydoctheme_dark.css applied to <div class="contents local topic" id="contents">:

div.topic,
div.note {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: currentColor;
}

But now the HTML structure has changed to <nav class="contents local" id="contents"> so the CSS doesn't apply.

The source RST:

.. contents::
   :depth: 1
   :local: