= Theme Keys Reference

== Category keys

The following pages list the keys and acceptable values or value types that are available when creating a custom theme.
The keys are organized by category key.
Each category represents a common prefix under which the (property) keys are typically nested.

TIP: Keys can be nested wherever an underscore (`_`) or hyphen (`-`) appears in the name.
This nested structure is for organizational purposes only.
All keys are flatted when the theme is loaded (e.g., `text-align` nested under `base` becomes `base-text-align`).

The converter uses the values of these keys to control how most elements are arranged and styled in the PDF.
The default values listed in this section get inherited from the {url-repo-root}/data/themes/base-theme.yml[base theme^].

IMPORTANT: The {url-repo-root}/data/themes/default-theme.yml[default theme^] has a different set of values which are not shown in this guide.

When creating a theme that extends the base theme, all keys are optional.
Required keys are provided by the base theme.
Therefore, you only have to declare keys that you want to override.
