<refentry xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          xmlns:src="http://nwalsh.com/xmlns/litprog/fragment"
          xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
          version="5.0" xml:id="docbook.css.source">
  <refmeta>
    <refentrytitle>docbook.css.source</refentrytitle>
    <refmiscinfo class="other" otherclass="datatype">string</refmiscinfo>
  </refmeta>
  <refnamediv>
    <refname>docbook.css.source</refname>
    <refpurpose>Name of the default CSS input file</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <src:fragment xml:id="docbook.css.source.frag"><xsl:param name="docbook.css.source">docbook.css.xml</xsl:param></src:fragment>
  </refsynopsisdiv>

  <refsection><info><title>Description</title></info>

<para>The <parameter>docbook.css.source</parameter> parameter
specifies the name of the file containing the default DocBook
CSS styles.  Those styles are necessary when the
<parameter>make.clean.html</parameter> parameter is nonzero.</para>

<para>The file is a well-formed XML file that
must consist of a single <tag>style</tag> root
element that contains CSS styles as its text content.
The default value of the parameter (and filename)
is <literal>docbook.css.xml</literal>.
The stylesheets ship with the default file. You can substitute
your own and specify its path in this parameter.</para>

<para>If <parameter>docbook.css.source</parameter> is not blank,
and <parameter>make.clean.html</parameter> is nonzero, then
the stylesheet takes the following actions:</para>

<orderedlist>
  <listitem>
    <para>The stylesheet uses the XSLT <literal>document()</literal>
    function to open the file specified by the parameter and
    load it into a variable.</para>
  </listitem>
  <listitem>
    <para>The stylesheet forms an output pathname consisting of the
    value of the <parameter>base.dir</parameter> parameter (if it is set)
    and the value of <parameter>docbook.css.source</parameter>,
    with the <literal>.xml</literal> suffix stripped off.
    </para>
  </listitem>
  <listitem>
    <para>The stylesheet removes the <tag>style</tag>
    wrapper element and writes just the CSS text content to the output file.</para>
  </listitem>
  <listitem>
    <para>The stylesheet adds a <tag>link</tag> element to the
    HTML <tag>HEAD</tag> element to reference the external CSS stylesheet.
    For example:</para>
    <programlisting>&lt;link rel="stylesheet" href="docbook.css" type="text/css"&gt;
    </programlisting>
    <para>However, if the <parameter>docbook.css.link</parameter>
    parameter is set to zero, then no <tag>link</tag> is written
    for the default CSS file.  That is useful if a custom
    CSS file will import the default CSS stylesheet to ensure
    proper cascading of styles.</para>
  </listitem>
</orderedlist>

<para>If the <parameter>docbook.css.source</parameter> parameter
is changed from its default <literal>docbook.css.xml</literal> to blank,
then no default CSS is generated. Likewise if the
<parameter>make.clean.html</parameter> parameter is set to zero,
then no default CSS is generated. The 
<parameter>custom.css.source</parameter> parameter can be used
instead to generate a complete custom CSS file.</para>

<para>You can use the <parameter>generate.css.header</parameter>
parameter to instead write the CSS to each HTML <tag>HEAD</tag>
element in a <tag>style</tag> tag instead of an external CSS file.</para>

  </refsection>
</refentry>