\documentclass[a4paper, 10pt]{ctexart}
\usepackage{geometry}
\geometry{
  top=1in,
  inner=1in,
  outer=1in,
  bottom=1in,
  headheight=3ex,
  headsep=2ex
}
\usepackage{tabu}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{booktabs}
\usepackage{amssymb,amsmath}
\usepackage{ifxetex,ifluatex}

\linespread{1.2}\selectfont                       % 行距
\XeTeXlinebreaklocale "zh"                        % 针对中文自动换行
\XeTeXlinebreakskip = 0pt plus 1pt                % 字与字之间加入 0pt 至 1pt 的间距，确保左右对齐
\parindent 0em                                    % 段落缩进
\setlength{\parskip}{20pt}                        % 段落间距
\ifxetex
  \usepackage{xltxtra,xunicode}
\fi
$if(mainfont)$
    \setmainfont{$mainfont$}
$endif$
$if(sansfont)$
    \setsansfont{$sansfont$}
$endif$
$if(monofont)$
    \setmonofont{$monofont$}
$endif$
$if(mathfont)$
    \setmathfont{$mathfont$}
$endif$

% use microtype if available
\IfFileExists{microtype.sty}{\usepackage{microtype}}{}
$if(geometry)$
\usepackage[$for(geometry)$$geometry$$sep$,$endfor$]{geometry}
$endif$
$if(natbib)$
\usepackage{natbib}
\bibliographystyle{plainnat}
$endif$
$if(biblatex)$
\usepackage{biblatex}
$if(biblio-files)$
\bibliography{$biblio-files$}
$endif$
$endif$
\usepackage{textcomp}
\usepackage{listings}
$if(lhs)$
\lstnewenvironment{code}{\lstset{language=Haskell,basicstyle=\small\ttfamily}}{}
$endif$
$if(highlighting-macros)$
$highlighting-macros$
$endif$
$if(verbatim-in-note)$
\usepackage{fancyvrb}
$endif$
$if(tables)$
\usepackage{longtable}
$endif$

\usepackage{graphicx}
\usepackage{caption}

% We will generate all images so they have a width \maxwidth. This means
% that they will get their normal width if they fit onto the page, but
% are scaled down if they would overflow the margins.
\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth
\else\Gin@nat@width\fi}
\makeatother
\let\Oldincludegraphics\includegraphics
\renewcommand{\includegraphics}[1]{\Oldincludegraphics[width=0.7\maxwidth]{#1}}
\ifxetex
  \usepackage[setpagesize=false, % page size defined by xetex
              unicode=false, % unicode breaks when used with xetex
              xetex]{hyperref}
\else
  \usepackage[unicode=true]{hyperref}
\fi
\hypersetup{breaklinks=true,
            bookmarks=true,
            pdfauthor={$author-meta$},
            pdftitle={$title-meta$},
            colorlinks=true,
            urlcolor=$if(urlcolor)$$urlcolor$$else$blue$endif$,
            linkcolor=$if(linkcolor)$$linkcolor$$else$magenta$endif$,
            pdfborder={0 0 0}}
\urlstyle{same}  % don't use monospace font for urls
$if(links-as-notes)$
% Make links footnotes instead of hotlinks:
\renewcommand{\href}[2]{#2\footnote{\url{#1}}}
$endif$
$if(strikeout)$
\usepackage[normalem]{ulem}
% avoid problems with \sout in headers with hyperref:
\pdfstringdefDisableCommands{\renewcommand{\sout}{}}
$endif$
\setlength{\parindent}{10pt}
%\setlength{\parskip}{6pt plus 2pt minus 1pt}
\setlength{\emergencystretch}{3em}  % prevent overfull lines
\usepackage{titling}
%\setlength{\droptitle}{-8em}  % 将标题移动至页面上方

\usepackage{fancyhdr}
\usepackage{lastpage}
\pagestyle{fancyplain}

$if(numbersections)$
\setcounter{secnumdepth}{5}
$else$
\setcounter{secnumdepth}{0}
$endif$
$if(verbatim-in-note)$
\VerbatimFootnotes % allows verbatim text in footnotes
$endif$
$if(lang)$
\ifxetex
  \usepackage{polyglossia}
  \setmainlanguage{$mainlang$}
\else
  \usepackage[$lang$]{babel}
\fi
$endif$
$for(header-includes)$
$header-includes$
$endfor$

$if(title)$
\title{$title$}
$endif$
\author{$for(author)$$author$$sep$ \and $endfor$}
\date{$date$}

%%%% 段落首行缩进两个字 %%%%
\makeatletter
\let\@afterindentfalse\@afterindenttrue
\@afterindenttrue
\makeatother
\setlength{\parindent}{2em}  %中文缩进两个汉字位

%%%% 下面的命令设置行间距与段落间距 %%%%
\linespread{1.4}
\setlength{\parskip}{1ex}
\setlength{\parskip}{0.5\baselineskip}

\input{revision}

% fix build, see https://github.com/laboon/ebook/issues/139#issuecomment-408696480
\newcommand{\passthrough}[1]{\lstset{mathescape=false}#1\lstset{mathescape=true}}

\begin{document}
\newcommand{\tightlist}{%
\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}

\thispagestyle{plain}
\begin{center}
  
  {\LARGE\textbf{现代 C++ 教程：高速上手 C++11/14/17/20}}
  
  \vspace{1em}
  {\large 欧长坤 (hi[at]changkun.de)}
  
  \vspace{1ex}
  最后更新 \today - \revision

  \vspace{1ex}
  \textbf{注意}

  \noindent 此 PDF 的内容可能过期，请检查\href{https://changkun.de/modern-cpp}{本书网站}以及 \href{https://github.com/changkun/modern-cpp-tutorial}{GitHub 仓库}以获取最新内容。

  \vspace{1em}
  \textbf{\large 版权声明}

  \noindent 本书系\href{https://github.com/changkun}{欧长坤}著，采用“知识共享署名-非商业性使用-禁止演绎 4.0 国际许可协议 (CC BY-NC-ND)”进行许可。\texttt{\small https://creativecommons.org/licenses/by-nc-nd/4.0/}

  \vspace{7em}
  \includegraphics{../../assets/cover-2nd}

\end{center}

$for(include-before)$
$include-before$

$endfor$

{
\newpage
\hypersetup{linkcolor=black}
\setcounter{tocdepth}{3}
\tableofcontents
}
\newpage

$body$

$if(natbib)$
$if(biblio-files)$
$if(biblio-title)$
$if(book-class)$
\renewcommand\bibname{$biblio-title$}
$else$
\renewcommand\refname{$biblio-title$}
$endif$
$endif$
\bibliography{$biblio-files$}

$endif$
$endif$
$if(biblatex)$
\printbibliography$if(biblio-title)$[title=$biblio-title$]$endif$

$endif$
$for(include-after)$
$include-after$

$endfor$
\end{document}