diff --git a/tex/pkulogo.eps b/tex/pkulogo.eps
index 35c1a90..e5b6fd6 100644
--- a/tex/pkulogo.eps
+++ b/tex/pkulogo.eps
@@ -21,6 +21,7 @@
 %
 % This work consists of the following files:
 %   pkuthss.cls
+%   pkuthss.def
 %   pkuthss-gbk.def
 %   pkuthss-utf8.def
 %   pkulogo.eps
diff --git a/tex/pkuthss-gbk.def b/tex/pkuthss-gbk.def
index 8f7554f..bb09161 100644
--- a/tex/pkuthss-gbk.def
+++ b/tex/pkuthss-gbk.def
@@ -17,6 +17,7 @@
 %
 % This work consists of the following files:
 %   pkuthss.cls
+%   pkuthss.def
 %   pkuthss-gbk.def
 %   pkuthss-utf8.def
 %   pkulogo.eps
@@ -33,7 +34,6 @@
 \def\label@cmajor{专\hphantom{汉字}业：}
 \def\label@direction{研究方向：}
 \def\label@cmentor{导\hphantom{汉字}师：}
-\def\label@ementor{Directed by\ }
 \def\label@ckeywords{关键词：}
 \def\label@blindcover{（匿名评阅论文封面）}
 \def\label@blindctitle{中文题目：}
@@ -44,18 +44,8 @@
 
 \def\titlepagename{封面}
 \def\cuniversity{北京大学}
-\def\euniversity{Peking University}
 \def\cthesisname{博士学位论文}
-\def\ethesisname{Doctor Thesis}
-\def\thesiscover{}
 \def\cabstractname{摘要}
-\def\eabstractname{ABSTRACT}
-
-\ifthss@opt@ugly
-\def\label@ekeywords{KEY WORDS:\ }
-\else
-\def\label@ekeywords{KEYWORDS:\ }
-\fi
 
 \endinput
 % vim:ft=tex:ts=2:sw=2
diff --git a/tex/pkuthss-utf8.def b/tex/pkuthss-utf8.def
index 76b8573..afed37b 100644
--- a/tex/pkuthss-utf8.def
+++ b/tex/pkuthss-utf8.def
@@ -17,6 +17,7 @@
 %
 % This work consists of the following files:
 %   pkuthss.cls
+%   pkuthss.def
 %   pkuthss-gbk.def
 %   pkuthss-utf8.def
 %   pkulogo.eps
@@ -33,7 +34,6 @@
 \def\label@cmajor{涓揬hphantom{姹夊瓧}涓氾細}
 \def\label@direction{鐮旂┒鏂瑰悜锛殅
 \def\label@cmentor{瀵糪hphantom{姹夊瓧}甯堬細}
-\def\label@ementor{Directed by\ }
 \def\label@ckeywords{鍏抽敭璇嶏細}
 \def\label@blindcover{锛堝尶鍚嶈瘎闃呰鏂囧皝闈級}
 \def\label@blindctitle{涓枃棰樼洰锛殅
@@ -44,18 +44,8 @@
 
 \def\titlepagename{灏侀潰}
 \def\cuniversity{鍖椾含澶у}
-\def\euniversity{Peking University}
 \def\cthesisname{鍗氬＋瀛︿綅璁烘枃}
-\def\ethesisname{Doctor Thesis}
-\def\thesiscover{}
 \def\cabstractname{鎽樿}
-\def\eabstractname{ABSTRACT}
-
-\ifthss@opt@ugly
-\def\label@ekeywords{KEY WORDS:\ }
-\else
-\def\label@ekeywords{KEYWORDS:\ }
-\fi
 
 \endinput
 % vim:ft=tex:ts=2:sw=2
diff --git a/tex/pkuthss.cls b/tex/pkuthss.cls
index 2abf2d7..60efd68 100644
--- a/tex/pkuthss.cls
+++ b/tex/pkuthss.cls
@@ -17,6 +17,7 @@
 %
 % This work consists of the following files:
 %   pkuthss.cls
+%   pkuthss.def
 %   pkuthss-gbk.def
 %   pkuthss-utf8.def
 %   pkulogo.eps
@@ -85,21 +86,7 @@
 \RequirePackage[normalem]{ulem}
 % `\AtEndOfClass' used to avoid `PDF destination not defined' with setspace.
 \AtEndOfClass{\RequirePackage{hyperref}}
-
-\ifthss@opt@gbk
-	\input{pkuthss-gbk.def}
-	\ifxetex
-		% No support for XeLaTeX compilation in non-unicode encoding, i.e. GBK.
-		\ClassError{pkuthss}%
-			{XeLaTeX compilation is not supported without UTF-8}%
-			{%
-				XeLaTeX compilation without UTF-8 is very problematic.\MessageBreak
-				Therefore please use UTF-8 encoding for the LaTeX code.%
-			}
-	\fi
-\else
-	\input{pkuthss-utf8.def}
-\fi
+\input{pkuthss.def}
 
 \ifthss@opt@pkufont
 	% Use Times New Roman / Arial according to school regulation.
diff --git a/tex/pkuthss.def b/tex/pkuthss.def
new file mode 100644
index 0000000..4042a01
--- /dev/null
+++ b/tex/pkuthss.def
@@ -0,0 +1,55 @@
+% Peking University dissertation document class
+%
+% Copyright (c) 2021 Casper Ti. Vector
+%
+% This work may be distributed and/or modified under the conditions of the
+% LaTeX Project Public License, either version 1.3 of this license or (at
+% your option) any later version.
+% The latest version of this license is in
+%   https://www.latex-project.org/lppl.txt
+% and version 1.3 or later is part of all distributions of LaTeX version
+% 2005/12/01 or later.
+%
+% This work has the LPPL maintenance status `maintained'.
+% The current maintainer of this work is Casper Ti. Vector.
+%
+% This work consists of the following files:
+%   pkuthss.cls
+%   pkuthss.def
+%   pkuthss-gbk.def
+%   pkuthss-utf8.def
+%   pkulogo.eps
+%   pkuword.eps
+
+\ProvidesFile{pkuthss.def}
+	[2021/03/29 v1.9.0 Labels and captions for the pkuthss document class]
+
+\def\label@ementor{Directed by\ }
+\def\euniversity{Peking University}
+\def\ethesisname{Doctor Thesis}
+\def\thesiscover{}
+\def\eabstractname{ABSTRACT}
+
+\ifthss@opt@ugly
+	\def\label@ekeywords{KEY WORDS:\ }
+\else
+	\def\label@ekeywords{KEYWORDS:\ }
+\fi
+
+\ifthss@opt@gbk
+	\input{pkuthss-gbk.def}
+	\ifxetex
+		% No support for XeLaTeX compilation in non-unicode encoding, i.e. GBK.
+		\ClassError{pkuthss}%
+			{XeLaTeX compilation is not supported without UTF-8}%
+			{%
+				XeLaTeX compilation without UTF-8 is very problematic.\MessageBreak
+				Therefore please use UTF-8 encoding for the LaTeX code.%
+			}
+	\fi
+\else
+	\input{pkuthss-utf8.def}
+\fi
+
+\endinput
+% vim:ft=tex:ts=2:sw=2
diff --git a/tex/pkuword.eps b/tex/pkuword.eps
index 88bbca5..0d6cc95 100644
--- a/tex/pkuword.eps
+++ b/tex/pkuword.eps
@@ -21,6 +21,7 @@
 %
 % This work consists of the following files:
 %   pkuthss.cls
+%   pkuthss.def
 %   pkuthss-gbk.def
 %   pkuthss-utf8.def
 %   pkulogo.eps