.. versionadded:: 0.6

Sphinx supports changing the appearance of its HTML output via themes. A theme is a collection of HTML templates, stylesheet(s) and other static files. Additionally, it has a configuration file which specifies from which theme to inherit, which highlighting style to use, and what options exist for customizing the theme's look and feel.

Themes are meant to be project-unaware, so they can be used for different projects without change.

Themes take the form of either a directory or a zipfile (whose name is the theme name), containing the following:

• A :file:`theme.conf` file.
• HTML templates, if needed.
• A static/ directory containing any static files that will be copied to the output static directory on build. These can be images, styles, script files.

The :file:`theme.conf` file is in INI format [1] (readable by the standard Python :mod:`ConfigParser` module) and has the following structure:

[theme]
inherit = base theme
stylesheet = main CSS name
pygments_style = stylename
sidebars = localtoc.html, relations.html, sourcelink.html, searchbox.html

[options]
variable = default value

• The inherit setting gives the name of a "base theme", or none. The base theme will be used to locate missing templates (most themes will not have to supply most templates if they use basic as the base theme), its options will be inherited, and all of its static files will be used as well. If you want to also inherit the stylesheet, include it via CSS' @import in your own.
• The stylesheet setting gives the name of a CSS file which will be referenced in the HTML header. If you need more than one CSS file, either include one from the other via CSS' @import, or use a custom HTML template that adds <link rel="stylesheet"> tags as necessary. Setting the :confval:`html_style` config value will override this setting.
• The pygments_style setting gives the name of a Pygments style to use for highlighting. This can be overridden by the user in the :confval:`pygments_style` config value.
• The pygments_dark_style setting gives the name of a Pygments style to use for highlighting when the CSS media query (prefers-color-scheme: dark) evaluates to true. It is injected into the page using :meth:`~Sphinx.add_css_file()`.
• The sidebars setting gives the comma separated list of sidebar templates for constructing sidebars. This can be overridden by the user in the :confval:`html_sidebars` config value.
• The options section contains pairs of variable names and default values. These options can be overridden by the user in :confval:`html_theme_options` and are accessible from all templates as theme_<name>.

.. versionadded:: 1.7
   sidebar settings

As a way to distribute your theme, you can use Python package. Python package brings to users easy setting up ways.

To distribute your theme as a Python package, please define an entry point called sphinx.html_themes in your setup.py file, and write a setup() function to register your themes using add_html_theme() API in it:

# 'setup.py'
setup(
    ...
    entry_points = {
        'sphinx.html_themes': [
            'name_of_theme = your_package',
        ]
    },
    ...
)

# 'your_package.py'
from os import path

def setup(app):
    app.add_html_theme('name_of_theme', path.abspath(path.dirname(__file__)))

If your theme package contains two or more themes, please call add_html_theme() twice or more.

.. versionadded:: 1.2
   'sphinx_themes' entry_points feature.

.. deprecated:: 1.6
   ``sphinx_themes`` entry_points has been deprecated.

.. versionadded:: 1.6
   ``sphinx.html_themes`` entry_points feature.

The :doc:`guide to templating <templating>` is helpful if you want to write your own templates. What is important to keep in mind is the order in which Sphinx searches for templates:

• First, in the user's templates_path directories.
• Then, in the selected theme.
• Then, in its base theme, its base's base theme, etc.

When extending a template in the base theme with the same name, use the theme name as an explicit directory: {% extends "basic/layout.html" %}. From a user templates_path template, you can still use the "exclamation mark" syntax as described in the templating document.

Since theme options are meant for the user to configure a theme more easily, without having to write a custom stylesheet, it is necessary to be able to template static files as well as HTML files. Therefore, Sphinx supports so-called "static templates", like this:

If the name of a file in the static/ directory of a theme (or in the user's static path, for that matter) ends with _t, it will be processed by the template engine. The _t will be left from the final file name. For example, the classic theme has a file static/classic.css_t which uses templating to put the color options into the stylesheet. When a documentation is built with the classic theme, the output directory will contain a _static/classic.css file where all template tags have been processed.