\SimpleSystemTeX allows users to customize \newconcept{Style Code} by using the \cs{SetStyle} command in the preamble, thereby setting or modifying the styling of various document components. In addition to standard \LaTeX\ commands, users can also utilize \newconcept{Display Arguments} prefixed with \texttt{@} within the style code to dynamically extract document content. The values of these arguments can similarly be evaluated in conditional statements to achieve highly flexible typesetting effects.

\UserCommand{Configure Style}{
    \cs{SetStyle}
    \{\meta{style}\}
    \{\meta{style code}\longarg\}
}[
    - \meta{style} : The name of the style to be set or modified.
][
    - \meta{style code}\longarg\ : The \LaTeX\ code used to define the appearance of the style. You may use standard \LaTeX\ commands for typesetting, display arguments prefixed with \texttt{@} , and the following conditional statements prefixed with \texttt{\#} :
        - - \texttt{\#ifempty} : Evaluates whether a display argument is empty.
        \LocalUsage{ifempty}(\#ifempty){
            \upshape
            \#ifempty
            @\meta{argument}
            \{\meta{true code}\longarg\}
            \{\meta{false code}\longarg\}
        }
        - - \texttt{\#ifis} : Evaluates whether a display argument, after one level of expansion, equals a
        \par\indent\indent\indent\indent specific value.
        \LocalUsage{ifis}(\#ifis){
            \upshape
            \#ifis
            @\meta{argument}
            \{\meta{value}\}
            \{\meta{true code}\longarg\}
            \{\meta{false code}\longarg\}
        }
        - - \texttt{\#ifequal} : Evaluates whether two display arguments, after one level of expansion,
        \par\indent\indent\indent\indent\indent are equal to each other.
        \LocalUsage{ifequal}(\#ifequal){
            \upshape
            \#ifequal
            @\meta{argument1}
            @\meta{argument2}
            \{\meta{true code}\longarg\}
            \{\meta{false code}\longarg\}
        }
]

When writing style code, please ensure that a display argument does not immediately follow any macro command, as this may lead to syntax parsing errors. You must insert a space before the \texttt{@} to prevent this issue, for example: \cs{par}\texttt{ @\meta{argument}} .

\newpage Customizable styles and their respective available display arguments include:

\List{TOC Style}(\large Table of Contents){
    \par\medskip{}
    - \textbf{\texttt{TOCTitle} : Title of the table of contents}.
    - \textbf{\texttt{TOCPartTitle} : Part title in the table of contents}.
        - - \texttt{@part} : Part.
    - \textbf{\texttt{TOCSection} : Section entry in the table of contents}.
        - - \texttt{@section} : Entry section file name.
        - - \texttt{@sectionname} : Entry section's display name.
        - - \texttt{@part} : Part containing the entry section.
        - - \texttt{@group} , \texttt{@subgroup} ... : Top-level group, second-level group... containing the entry section.
        - - \texttt{@sectionpath} : Entry section path.
        - - \texttt{@sectionpage} : Page number where the entry section heading is located.
        - - \texttt{@sectionparameter} : Custom parameter of the entry section.
}

\List{Section Style}(\large Section){
    \par\medskip{}
    - \textbf{\texttt{SectionHeading} : Section Heading}.
        - - \texttt{@section} : Section file name.
        - - \texttt{@sectionname} : Section's display name.
        - - \texttt{@part} : Part containing the section.
        - - \texttt{@group} , \texttt{@subgroup} ... : Top-level group, second-level group... containing the section.
        - - \texttt{@sectionpath} : Section path.
        - - \texttt{@sectionpage} : Page number where the section heading is located.
        - - \texttt{@sectionparameter} : Custom parameter of the section.
    - \textbf{\meta{block type} : Block}.
        - - \texttt{@section} , \texttt{@sectionname} ... : (Display arguments of the containing section)
        - - \texttt{@block} : Block's label, not available for anonymous blocks.
        - - \texttt{@blockname} : Block's display name.
        - - \texttt{@blockparameter} : Custom parameter of the block.
        - - \texttt{@blockcontent} : Block's content.
}

\newpage

\List{Block Index Style}(\large Block Index){
    \par\medskip{}
    - \textbf{\texttt{IndexTitle} , \texttt{IndexSubtitle} ... : Titles of top-level group, second-level group... in the block index}.
        - - \texttt{@section} , \texttt{@sectionname} ... : (Display arguments of the containing section)
        - - \texttt{@indexgroup} , \texttt{@indexsubgroup} ... : Top-level group, second-level group... in the block index's scope path.
        - - \texttt{@indexparameter} : Custom parameter of the block index.
    - \textbf{\texttt{IndexBlock} : Entry in the block index}.
        - - \texttt{@section} , \texttt{@sectionname} ... : (Display arguments of the containing section)
        - - \texttt{@indexparameter} : Custom parameter of the block index.
        - - \texttt{@indexblock} : Entry block's label, not available for anonymous blocks.
        - - \texttt{@indexblockname} : Entry block's display name.
        - - \texttt{@indexblockparameter} : Custom parameter of the entry block.
        - - \texttt{@indexsection} : Section file name containing the entry block.
        - - \texttt{@indexsectionname} : Display name of the section containing the entry block.
        - - \texttt{@indexpart} : Part containing the entry block.
        - - \texttt{@indexgroup} , \texttt{@indexsubgroup} ... : Top-level group, second-level group... containing the entry block.
        - - \texttt{@indexsectionpath} : Section path containing the entry block.
        - - \texttt{@indexsectionparameter} : Custom parameter of the section containing the entry block.
}

\List{Cross-Reference Style}(\large Cross-Reference){
    \par\medskip{}
    - \textbf{\texttt{SectionLink} : Section Link}.
        - - \texttt{@section} , \texttt{@sectionname} ... : (Display arguments of the containing section)
        - - \texttt{@block} , \texttt{@blockname} ... : (Display arguments of the containing block)
        - - \texttt{@linktext} : Link text.
        - - \texttt{@targetsection} : Target section file name.
        - - \texttt{@targetsectionname} : Target section's display name.
        - - \texttt{@targetpart} : Part containing the target section.
        - - \texttt{@targetgroup} , \texttt{@targetsubgroup} ... : Top-level group, second-level group... containing the target section.
        - - \texttt{@targetsectionpath} : Target section path.
        - - \texttt{@targetsectionpage} : Page number where the target section heading is located.
        - - \texttt{@targetsectionparameter} : Custom parameter of the target section.
    \newpage{}
    - \textbf{\texttt{BlockLink} : Block Link}.
        - - \texttt{@section} , \texttt{@sectionname} ... : (Display arguments of the containing section)
        - - \texttt{@block} , \texttt{@blockname} ... : (Display arguments of the containing block)
        - - \texttt{@linktext} : Link text.
        - - \texttt{@targetblock} : Target block's label, not available for anonymous blocks.
        - - \texttt{@targetblockname} : Target block's display name.
        - - \texttt{@targetblockparameter} : Custom parameter of the target block.
    - \textbf{\texttt{IndexLink} : Index Link}.
        - - \texttt{@section} , \texttt{@sectionname} ... : (Display arguments of the containing section)
        - - \texttt{@block} , \texttt{@blockname} ... : (Display arguments of the containing block)
        - - \texttt{@linktext} : Link text.
        - - \texttt{@targetgroup} , \texttt{@targetsubgroup} ... : Top-level group, second-level group... in the target index's scope path.
        - - \texttt{@targetindexparameter} : Custom parameter of the target index.
}

Not all display arguments are intended for rendering content. For instance, if \texttt{@section} contains special characters, you might use \texttt{@sectionname} as a substitute. In such scenarios, \texttt{@section} should be used to provide the section file name for conditional evaluation, whereas \texttt{@sectionname} should be used for display in the document. Please select the appropriate display arguments according to your specific requirements when authoring style code.

Please avoid the following practices within your style code, as they may lead to errors such as scope conflicts among display arguments:

\BadPractice{Style Code-Bad Practice}{
    - Do not leave label-type arguments containing special characters, like \texttt{@section}, directly exposed in the style code.
    - Do not nest blocks in the style code of \meta{block type} .
    - Do not nest links in the style code of \textbf{\texttt{SectionLink}}, \textbf{\texttt{BlockLink}}, or \textbf{\texttt{IndexLink}}.
    - Do not use \texttt{@blockcontent} in the style code of \textbf{\texttt{SectionLink}}, \textbf{\texttt{BlockLink}}, or \textbf{\texttt{IndexLink}}.
    - Do not compare path-type arguments like \texttt{@sectionpath} with other arguments like \texttt{@section} or their concatenated values, because they possess different \TeX\ catcodes.
}

Before authoring style code, please review the \seclink{StyleCodePresetValues}. \textcolor{orange}{It is highly recommended to copy the specific portions you intend to modify into the preamble first}, and then base your further adjustments upon them.

\newpage