use custom fonts. seems good

beamerthemeSimple.sty

@@ -3,7 +3,7 @@
 % This file may be distributed and/or modified
 % under the LaTeX Project Public License
 \usepackage{libertine}
-\RequirePackage[english]{babel}
+\RequirePackage[chinese, provide=*]{babel}
 \RequirePackage{fancyhdr}        % header footer
 \RequirePackage{xcolor}
 \RequirePackage{bookmark}
@@ -20,10 +20,32 @@
 \RequirePackage{subcaption}
 \RequirePackage{amsmath}
 \RequirePackage{amsthm}
-\RequirePackage[utf8]{inputenc}
-\RequirePackage{CJKutf8}
-\def\zh#1{\begin{CJK}{UTF8}{gbsn}#1\end{CJK}}
-\RequirePackage{aliascnt}
+% \RequirePackage[utf8]{inputenc}
+% \RequirePackage{CJKutf8}
+% \def\zh#1{\begin{CJK}{UTF8}{gbsn}#1\end{CJK}}
+% \RequirePackage{aliascnt}
+\RequirePackage{ctex}
+\RequirePackage{fontspec}
+\RequirePackage{xeCJK}
+% infact italic and BoldItalic fonts are missing
+\setCJKmainfont{LXGWNeoZhiSong}[
+  Path=./fonts/,
+  Extension = .ttf,
+  UprightFont=*,
+  BoldFont=*,
+  ItalicFont=*,
+  BoldItalicFont=*
+]
+\setCJKsansfont{LXGWWenKai}[
+  Path=./fonts/,
+  Extension = .ttf,
+  UprightFont=*-Regular,
+  BoldFont=*-Bold,
+  ItalicFont=*-Regular,
+  BoldItalicFont=*-Regular,
+]
+\XeTeXlinebreaklocale "zh" 
+\XeTeXlinebreakskip = 0pt plus 1pt 
 
 % a color box
 \RequirePackage[breakable, theorems, skins]{tcolorbox}

main.tex

@@ -1,8 +1,8 @@
 \documentclass{beamer}
 
-\title[template example]{Minimizing the Sum of Piecewise Linear Convex Functions}
+\title[中文测试]{Minimizing the Sum of Piecewise Linear Convex Functions - 这是很长很长很长很长的兼有中文和英文的标题}
 \date{\today}
-\author{\texorpdfstring{\zh{丛宇}}{Yu Cong}}
+\author{丛宇}
 % \AtBeginSection[]{
 %     \frame{\frametitle{Outline}\tableofcontents[currentsection, 
 %     subsectionstyle=show/show/shaded]}
@@ -17,13 +17,13 @@
     \titlepage
 \end{frame}
 
-\begin{frame}[plain]{Plan}
+\begin{frame}[plain]{计划}
     \tableofcontents
 \end{frame}
 
-\section{Problems \& Definitions}
-\begin{frame}{$\min \sum f_i(a_i\cdot x-b_i)$}
-\begin{problem}
+\section{Problems \& Definitions 问题定义}
+\begin{frame}{$\min \sum f_i(a_i\cdot x-b_i)$ 中文测试}
+\begin{problem} regular 中文 jjjfff
     Given $n$ piecewise linear convex functions $f_1,...,f_n:\R \to \R$ of total $m$ breakpoints, and $n$ linear functions $a_i\cdot x-b_i:\R^d\to \R$, find $\min_x \sum_i f_i(a_i\cdot x-b_i)$.
 \end{problem}
 \begin{figure}