在这个帖子，我想知道如何修改文档各部分标题的布局。我想知道如何在部分标题的末尾和章节标题的开头之间插入空格。这是我的 MWE：
\documentclass[hidelinks,12pt,twoside,openright,a4paper]{book}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
\usepackage{setspace}
\usepackage{lipsum}
\usepackage{tocloft}
\setlength{\cftbeforechapskip}{3pt}%espace entre chapitres
\renewcommand{\cftchapleader}{\cftdotfill{\cftdotsep}} % for chapters
\makeatletter
\renewcommand\l@part[2]{%
\ifnum \c@tocdepth >-2\relax
\addpenalty{-\@highpenalty}%
\addvspace{2.25em \@plus\p@}%
\setlength\@tempdima{3em}%
\begingroup
\parindent \z@ \rightskip \@pnumwidth
\parfillskip -\@pnumwidth
{\hfill\parbox{0.6\linewidth}{\centering\large \bfseries #1}\hfill
\hb@xt@\@pnumwidth{\hss #2%
\kern-\p@\kern\p@}}\par
\nobreak
\global\@nobreaktrue
\everypar{\global\@nobreakfalse\everypar{}}%
\endgroup
\fi}
\newcounter{partorder}
\newcommand{\partorder}{%
\ifcase\value{partorder}\or First\or Second\or Third\or Fourth\or Fifth\or Sixth\or Seventh\or Eighth\or Ninth\or Tenth\else ??(out range)\fi%
} % If you have more than 10 parts, you need extend this define
\def\@part[#1]#2{%
\ifnum \c@secnumdepth >-2\relax
\refstepcounter{part}\stepcounter{partorder}%
\addcontentsline{toc}{part}{\texorpdfstring{\partorder\space\partname\\#1}{\partorder\space\partname\ --\ #1}}%
\else
\addcontentsline{toc}{part}{#1}%
\fi
\markboth{}{}%
{\centering
\interlinepenalty \@M
\normalfont
\ifnum \c@secnumdepth >-2\relax
\huge\bfseries \partname\nobreakspace\thepart
\par
\vskip 20\p@
\fi
\Huge \bfseries #2\par}%
\@endpart}
\makeatother
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{fancyhdr}
\pagestyle{fancy}
% We don’t want chapter and section numbers
\renewcommand{\chaptermark}[1]{\markboth{#1}{}}
\renewcommand{\headrulewidth}{0pt}
\fancyhf{} % sets both header and footer to nothing
\fancyfoot{}
\fancyhead[LE,RO]{\thepage}
\fancyhead[CE]{\textit{A title}} % even pages: chapter title
\fancyhead[CO]{\textit\leftmark} % odd pages: book title
\setlength{\headheight}{15pt}
\usepackage{hyperref}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\title{A title}
\author{A name}
\date{}
\maketitle
\tableofcontents
\frontmatter
\part{\texorpdfstring{Why is Latex so complicated?\\Answer and questions}{Why is Latex so complicated?\ --\ Answer and questions}}
\chapter{A chapter}
\lipsum
\mainmatter
\part{How to customize a part section?}
\chapter{Another chapter}
\lipsum
\setcounter{part}{10}
\setcounter{partorder}{10}
\part{\texorpdfstring{How about more than 10 parts?\\You need define it in \textbackslash partorder command}{How about more than 10 parts?\ -- \ You need define it in \textbackslash partorder command}}
\chapter{Another chapter}
\backmatter
\end{document}