```tex \documentclass[xcolor=svgnames, aspectratio=169]{ctexbeamer} \usetheme{Warsaw} \useoutertheme[width=.15\paperwidth]{sidebar} \usepackage{lmodern} \title{版面居中} \date{2020年02月02日} \usepackage{xifthen} \usepackage{multido} % copied from https://tex.stackexchange.com/a/423246 \newcommand{\foo}[1]{% \multido{\i=1+1}{#1}{% \i~Foo }% } \makeatletter \newenvironment{myplainframe}[1][]{% \ifthenelse{\isnamedefined{beamer@sidebarwidth}}{% % Customize frametitle (changes from \defbeamertemplate*{frametitle}{sidebar % theme} in `beamerouterthemesidebar.sty' flagged with `% <- !') \setbeamertemplate{frametitle} {% \nointerlineskip% \ifbeamer@plainframe% \hbox{\usebeamercolor[bg]{frametitle}% \@tempdima\paperwidth%\advance\@tempdima-\beamer@sidebarwidth % <- ! \hskip-\beamer@leftmargin\vrule height\beamer@headheight width\@tempdima\hskip-\beamer@rightmargin}% \nointerlineskip% \fi% \vskip-\beamer@headheight% \vbox to \beamer@headheight{% \vfil \leftskip=-\beamer@leftmargin% \advance\leftskip by0.3cm% \rightskip=-\beamer@rightmargin% \advance\rightskip by0.3cm plus1fil% {\usebeamercolor[fg]{frametitle}\usebeamerfont{frametitle}\insertframetitle\par}% {\usebeamercolor[fg]{framesubtitle}\usebeamerfont{framesubtitle}\insertframesubtitle\par}% \vbox{}% \vskip-1em% \vfil }% }% \setbeamertemplate{background canvas} {% \ifbeamercolorempty[bg]{background canvas}{}{\color{bg}\vrule width\dimexpr\paperwidth+\beamer@leftsidebar\relax height\paperheight}% } % Customize the geometry (changes from options of geometry package in % `beamer.cls' flagged with `% <- !') \hoffset=-\beamer@leftsidebar \advance\textwidth\beamer@sidebarwidth \hsize\textwidth \columnwidth\textwidth }{% }% % \begin{frame}[plain,#1]% }{% \end{frame}% } \makeatother \begin{document} \begin{frame}[plain]{} 内容版面居中 \titlepage \end{frame} \begin{myplainframe} \centering 致谢页：内容版面居中 \end{myplainframe} \end{document} ```