Theming

Since version 3.0.0, GitBook can be easily themed. Books use the theme-default theme by default.

Caution: Custom theming can block some plugins from working correctly.

Structure of a theme

A theme is a plugin containing templates and assets. Overriding any individual template is optional, since themes always extend the default theme.

Extend/Customize theme in a book

Authors can extend the templates of a theme directly from their book's source (without creating an external theme). Templates will be resolved in the _layouts folder of the book first, then in the installed plugins/themes.

Extend instead of Forking

When you want to make your theme changes available to multiple books, instead of forking the default theme, you can extend it using the templating syntax:

{% extends template.self %}

{% block body %}
    {{ super() }}
    ... This will be added to the "body" block
{% endblock %}

Take a look at the API theme for a more complete example.

Publish a theme

Themes are published as plugins (see related docs) with a theme- prefix. For example the theme awesome will be loaded from the theme-awesome plugin, and then from the gitbook-plugin-theme-awesome NPM package.