Custom themes

A guide to creating and distributing custom themes.

Note

If you are looking for third party themes, they are listed in the MkDocs community wiki. If you want to share a theme you create, you should list it on the Wiki.

When creating a new theme, you can either follow the steps in this guide to create one from scratch or you can download the mkdocs-basic-theme as a basic, yet complete, theme with all the boilerplate required. You can find this base theme on GitHub. It contains detailed comments in the code to describe the different features and their usage.

Creating a custom theme

The bare minimum required for a custom theme is a main.html Jinja2 template file. This should be placed in a directory which will be the theme_dir and it should be created next to the mkdocs.yml configuration file. Within mkdocs.yml, specify the theme custom_dir option and set it to the name of the directory containing main.html. For example, given this example project layout:

mkdocs.yml
docs/
    index.md
    about.md
custom_theme/
    main.html
    ...

You would include the following settings in mkdocs.yml to use the custom theme directory:

theme:
    name: null
    custom_dir: 'custom_theme'

Note

Generally, when building your own custom theme, the theme name configuration setting would be set to null. However, if used in combination with the custom_dir configuration value a custom theme can be used to replace only specific parts of a built-in theme. For example, with the above layout and if you set name: "mkdocs" then the main.html file in the custom_dir would replace that in the theme but otherwise the mkdocs theme would remain the same. This is useful if you want to make small adjustments to an existing theme.

For more specific information, see styling your docs.

Basic theme

The simplest main.html file is the following:

<!DOCTYPE html>
<html>
  <head>
    <title>{% if page_title %}{{ page_title }} - {% endif %}{{ site_name }}</title>
  </head>
  <body>
    {{ content }}
  </body>
</html>

Article content from each page specified in mkdocs.yml is inserted using the {{ content }} tag. Style-sheets and scripts can be brought into this theme as with a normal HTML file. Navbars and tables of contents can also be generated and included automatically, through the nav and toc objects, respectively. If you wish to write your own theme, it is recommended to start with one of the built-in themes and modify it accordingly.

Note

As MkDocs uses Jinja as its template engine, you have access to all the power of Jinja, including template inheritance. You may notice that the themes included with MkDocs make extensive use of template inheritance and blocks, allowing users to easily override small bits and pieces of the templates from the theme [custom_dir]. Therefore, the built-in themes are implemented in a base.html file, which main.html extends. Although not required, third party template authors are encouraged to follow a similar pattern and may want to define the same blocks as are used in the built-in themes for consistency.

Template Variables

Each template in a theme is built with a template context. These are the variables that are available to themes. The context varies depending on the template that is being built. At the moment templates are either built with the global context or with a page specific context. The global context is used for HTML pages that don't represent an individual Markdown document, for example a 404.html page or search.html.

Global Context

The following variables are available globally on any template.

config

The config variable is an instance of MkDocs' config object generated from the mkdocs.yml config file. While you can use any config option, some commonly used options include:

nav

The nav variable is used to create the navigation for the documentation. Following is a basic usage example which outputs the first and second level navigation as a nested list.

{% if nav|length>1 %}
    <ul>
    {% for nav_item in nav %}
        {% if nav_item.children %}
            <li>{{ nav_item.title }}
                <ul>
                {% for nav_item in nav_item.children %}
                    <li class="{% if nav_item.active%}current{%endif%}">
                        <a href="{{ nav_item.url }}">{{ nav_item.title }}</a>
                    </li>
                {% endfor %}
                </ul>
            </li>
        {% else %}
            <li class="{% if nav_item.active%}current{%endif%}">
                <a href="{{ nav_item.url }}">{{ nav_item.title }}</a>
            </li>
        {% endif %}
    {% endfor %}
    </ul>
{% endif %}

The nav object also contains a homepage object, which points to the page object of the homepage. For example, you may want to access nav.homepage.url.

base_url

The base_url provides a relative path to the root of the MkDocs project. This makes it easy to include links to static assets in your theme. For example, if your theme includes a js folder, to include theme.js from that folder on all pages you would do this:

<script src="{{ base_url }}/js/theme.js"></script>

extra_css

Contains a list of URLs to the style-sheets listed in the extra_css config setting. Unlike the config setting, which contains local paths, this variable contains absolute paths from the homepage.

extra_javascript

Contains a list of URLs to the scripts listed in the extra_javascript config setting. Unlike the config setting, which contains local paths, this variable contains absolute paths from the homepage.

mkdocs_version

Contains the current MkDocs version.

build_date_utc

A Python datetime object that represents the date and time the documentation was built in UTC. This is useful for showing how recently the documentation was updated.

page

In templates which are not rendered from a Markdown source file, the page variable is None. In templates which are rendered from a Markdown source file, the page variable contains a page object with the following attributes:

page.title

Contains the Title for the current page.

page.content

The rendered Markdown as HTML, this is the contents of the documentation.

page.toc

An object representing the Table of contents for a page. Displaying the table of contents as a simple list can be achieved like this.

<ul>
{% for toc_item in page.toc %}
    <li><a href="{{ toc_item.url }}">{{ toc_item.title }}</a></li>
    {% for toc_item in toc_item.children %}
        <li><a href="{{ toc_item.url }}">{{ toc_item.title }}</a></li>
    {% endfor %}
{% endfor %}
</ul>

page.meta

A mapping of the metadata included at the top of the markdown page. In this example we define a source property above the page title.

source: generics.py
        mixins.py

# Page title

Content...

A template can access this metadata for the page with the meta.source variable. This could then be used to link to source files related to the documentation page.

{% for filename in page.meta.source %}
  <a class="github" href="https://github.com/.../{{ filename }}">
    <span class="label label-info">{{ filename }}</span>
  </a>
{% endfor %}

page.canonical_url

The full, canonical URL to the current page. This includes the site_url from the configuration.

page.edit_url

The full URL to the input page in the source repository. Typically used to provide a link to edit the source page.

page.url

The URL to the current page not including the site_url from the configuration.

page.is_homepage

Evaluates to True for the homepage of the site and False for all other pages. This can be used in conjunction with other attributes of the page object to alter the behavior. For example, to display a different title on the homepage:

{% if not page.is_homepage %}{{ page.title }} - {% endif %}{{ site_name }}

page.previous_page

The page object for the previous page. The usage is the same as for page.

page.next_page

The page object for the next page.The usage is the same as for page.

Extra Context

Additional variables can be passed to the template with the extra configuration option. This is a set of key value pairs that can make custom templates far more flexible.

For example, this could be used to include the project version of all pages and a list of links related to the project. This can be achieved with the following extra configuration:

extra:
    version: 0.13.0
    links:
        - https://github.com/mkdocs
        - https://docs.readthedocs.org/en/latest/builds.html#mkdocs
        - http://www.mkdocs.org/

And then displayed with this HTML in the custom theme.

{{ config.extra.version }}

{% if config.extra.links %}
  <ul>
  {% for link in config.extra.links %}
      <li>{{ link }}</li>
  {% endfor %}
  </ul>
{% endif %}

Search and themes

As of MkDocs 0.17 client side search support has been added to MkDocs via the search plugin. A theme needs to provide a few things for the plugin to work with the theme.

While the search plugin is activated by default, users can disable the plugin and themes should acount for this. It is recomended that theme templates wrap search specific markup with a check for the plugin:

{% if 'search' in config['plugins'] %}
    search stuff here...
{% endif %}

At its most basic functionality, the search plugin will simply provide an index file which is no more than a JSON file containing the content of all pages. The theme would need to implement its own search functionality client-side. However, with a few settings and the necessary templates, the plugin can provide a complete functioning client-side search tool based on lunr.js.

The following options can be set in the theme's configuration file, mkdocs_theme.yml:

include_search_page

Determines whether the search plugin expects the theme to provide a dedicated search page via a template located at search/search.html.

When include_search_page is set to true, the search template will be built and available at search/search.html. This method is used by the readthedocs theme.

When include_search_page is set to false or not defined, it is expected that the theme provide some other mechanisms for displaying search results. For example, the mkdocs theme displays results on any page via a modal.

search_index_only

Determines whether the search plugin should only generate a search index or a complete search solution.

When search_index_only is set to true or not defined, the search plugin makes no modifications to the Jinja environment. A complete solution using the provided index file is the responsability of the theme.

When search_index_only is set to false, then the search plugin modifies the Jinja environment by adding its own temaplates directory (with a lower precedence than the theme) and adds its scripts to the extra_javascript config setting.

The following HTML needs to be added to the theme so that the provided JavaScript is able to properly load Lunr.js and make relative links to the search results from the current page.

<script>var base_url = '{{ base_url }}';</script>

Note

The provided JavaScript will download the search index. For larger documentation projects this can be a heavy operation. In those cases, it is suggested that you either use search_index_only: true to only include search on one page or load the JavaScript on an event like a form submit.

The following HTML in a search/search.html template will add a full search implementation to your theme.

<h1 id="search">Search Results</h1>

<form action="search.html">
  <input name="q" id="mkdocs-search-query" type="text" >
</form>

<div id="mkdocs-search-results">
  Sorry, page not found.
</div>

The JavaScript in the plugin works by looking for the specific ID's used in the above HTML. The input for the user to type the search query must have the ID mkdocs-search-query and mkdocs-search-results is the div where the results will be placed.

Packaging Themes

MkDocs makes use of Python packaging to distribute themes. This comes with a few requirements.

To see an example of a package containing one theme, see the MkDocs Bootstrap theme and to see a package that contains many themes, see the MkDocs Bootswatch theme.

Note

It is not strictly necessary to package a theme, as the entire theme can be contained in the custom_dir. If you have created a "one-off theme," that should be sufficient. However, if you intend to distribute your theme for others to use, packaging the theme has some advantages. By packaging your theme, your users can more easily install it and they can then take advantage of the [custom_dir] to make tweaks to your theme to better suit their needs.

Package Layout

The following layout is recommended for themes. Two files at the top level directory called MANIFEST.in and setup.py beside the theme directory which contains an empty __init__.py file, a theme configuration file (mkdocs-theme.yml), and your template and media files.

.
|-- MANIFEST.in
|-- theme_name
|   |-- __init__.py
|   |-- mkdocs-theme.yml
|   |-- main.html
|   |-- styles.css
`-- setup.py

The MANIFEST.in file should contain the following contents but with theme_name updated and any extra file extensions added to the include.

recursive-include theme_name *.ico *.js *.css *.png *.html *.eot *.svg *.ttf *.woff
recursive-exclude * __pycache__
recursive-exclude * *.py[co]

The setup.py should include the following text with the modifications described below.

from setuptools import setup, find_packages

VERSION = '0.0.1'


setup(
    name="mkdocs-themename",
    version=VERSION,
    url='',
    license='',
    description='',
    author='',
    author_email='',
    packages=find_packages(),
    include_package_data=True,
    entry_points={
        'mkdocs.themes': [
            'themename = theme_name',
        ]
    },
    zip_safe=False
)

Fill in the URL, license, description, author and author email address.

The name should follow the convention mkdocs-themename (like mkdocs- bootstrap and mkdocs-bootswatch), starting with MkDocs, using hyphens to separate words and including the name of your theme.

Most of the rest of the file can be left unedited. The last section we need to change is the entry_points. This is how MkDocs finds the theme(s) you are including in the package. The name on the left is the one that users will use in their mkdocs.yml and the one on the right is the directory containing your theme files.

The directory you created at the start of this section with the main.html file should contain all of the other theme files. The minimum requirement is that it includes a main.html for the theme. It must also include a __init__.py file which should be empty, this file tells Python that the directory is a package.

Theme Configuration

A packaged theme is required to include a configuration file named mkdocs_theme.yml which is placed in the root of your template files. The file should contain default configuration options for the theme. However, if the theme offers no configuration options, the file is still required and can be left blank.

The theme author is free to define any arbitrary options deemed necessary and those options will be made available in the templates to control behavior. For example, a theme might want to make a sidebar optional and include the following in the mkdocs_theme.yml file:

show_sidebar: true

Then in a template, that config option could be referenced:

{% if config.theme.show_sidebar %}
<div id="sidebar">...</div>
{% endif %}

And the user could override the default in their project's mkdocs.yml config file:

theme:
    name: themename
    show_sidebar: false

In addition to arbitrary options defined by the theme, MkDocs defines a few special options which alters its behavior:

static_templates

This option mirrors the theme config option of the same name and allows some defaults to be set by the theme. Note that while the user can add templates to this list, the user cannot remove templates included in the theme's config.

extends

Defines a parent theme that this theme inherits from. The value should be the string name of the parent theme. Normal Jinja inheritance rules apply.

Plugins may also define some options which allow the theme to inform a plugin about which set of plugin options it expects. See the documentation for any plugins you may wish to support in your theme.

Distributing Themes

With the above changes, your theme should now be ready to install. This can be done with pip, using pip install . if you are still in the same directory as the setup.py.

Most Python packages, including MkDocs, are distributed on PyPI. To do this, you should run the following command.

python setup.py register

If you don't have an account setup, you should be prompted to create one.

For a much more detailed guide, see the official Python packaging documentation for Packaging and Distributing Projects.