docs(manual): add a FAQ entry for adjusting math font.

Author: fky2015

Diff for: bithesis.dtx

@@ -1317,6 +1317,22 @@
 %   个人简介。
 % \end{function}
 %
+% \section{常见问题和疑难解答}
+%
+% \subsection{如何修改数学公式的字体？}
+%
+% 本项目已经使用 \pkg{unicode-math} 宏包，
+% 可以在导言区使用 |\setmathfont{XITS Math}| 修改数学环境下字体：
+%
+% \begin{latex}
+%   \unimathsetup{bold-style=ISO}
+%   \setmathfont{XITS Math}
+% \end{latex}
+%
+% \textit{请事先安装 XITS 字体。}
+%
+% \textit{更多字体与使用方法请参考 \url{https://ctan.org/pkg/unicode-math?lang=zh}。}
+%
 % \section{\cls{bitreport.cls} 使用与配置}
 % \label{sec:bitreport}
 % 

Diff for: templates/graduate-thesis/bithesis.cls

@@ -460,7 +460,9 @@
     footskip = 2.6cm + 7bp - 2cm,
   }
 }
-\setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+\__bithesis_if_bachelor_thesis:T {
+  \setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+}
 \setmainfont{Times~New~Roman}
 \setromanfont{Times~New~Roman}
 \ctex_at_end_preamble:n {

Diff for: templates/paper-translation/bithesis.cls

@@ -460,7 +460,9 @@
     footskip = 2.6cm + 7bp - 2cm,
   }
 }
-\setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+\__bithesis_if_bachelor_thesis:T {
+  \setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+}
 \setmainfont{Times~New~Roman}
 \setromanfont{Times~New~Roman}
 \ctex_at_end_preamble:n {

Diff for: templates/undergraduate-thesis-en/bithesis.cls

@@ -460,7 +460,9 @@
     footskip = 2.6cm + 7bp - 2cm,
   }
 }
-\setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+\__bithesis_if_bachelor_thesis:T {
+  \setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+}
 \setmainfont{Times~New~Roman}
 \setromanfont{Times~New~Roman}
 \ctex_at_end_preamble:n {

Diff for: templates/undergraduate-thesis/bithesis.cls

@@ -460,7 +460,9 @@
     footskip = 2.6cm + 7bp - 2cm,
   }
 }
-\setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+\__bithesis_if_bachelor_thesis:T {
+  \setlength{\intextsep}{2\baselineskip plus 0.2\baselineskip minus 0.2\baselineskip}
+}
 \setmainfont{Times~New~Roman}
 \setromanfont{Times~New~Roman}
 \ctex_at_end_preamble:n {