# Syntactic sugar

Theme files can use syntactic sugar to make them easier to read and write. When theme files are read, any shorthand keys are “desugared” to their more verbose equivalents before they are passed to the stylesheet generator.

## Content

The authoring format of the `content` key is a DSL that supports field and variable references mixed with text.

You can reference DITA-OT variables by name by prefixing them with the number sign `#` and wrapping them in braces `{` `}.` For example:

    content: '{#copyright} {year} ACME Corporation'

desugars to

    content:
      - kind: variable
        value: copyright
      - kind: text
        value: ' '
      - kind: field
        value: year
      - kind: text
        value: ' ACME Corporation'

which would result in a line like this:

> © 2022 ACME Corporation

## Page dimensions

When page dimensions are defined using the `size` and `orientation` keys, they are desugared to `width` and `height` keys using a mapping table for known page sizes.

    page:
      size: A4

desugars to

    page:
      width: 210mm
      height: 297mm

## Header and footer

Style keys for `header` and `footer` are collected under the `odd` and `even` keys.

    header:
      color: silver
      odd:
        font-weight: bold

desugars to

    header:
      odd:
        font-weight: bold
        color: silver
      even:
        color: silver

## Topic titles

Style keys `h1`, `h2`, `h3`, and `h4` are desugared to `topic`, `topic-topic`, `topic-topic-topic`, and `topic-topic-topic-topic`, respectively.

    style:
      h2:
        font-weight: bold

desugars to

    header:
      topic-topic:
        font-weight: bold