% ============================================================
% 2026 年高教社杯全国大学生数学建模竞赛论文模板（B 题）
% ============================================================
\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{mcm26b-paper}[2026/09/11 MCM 2026 paper class]

% 电子版为默认模式；纸质版通过 class option `paper' 开启。
\newif\ifpaper
\paperfalse
\DeclareOption{paper}{\papertrue}
\DeclareOption{electronic}{\paperfalse}

% 将其余选项（如 zihao=-4、a4paper）交给 ctexart。
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{ctexart}}
\ProcessOptions\relax
\LoadClass{ctexart}

% ---------- 页面与基础宏包 ----------
\RequirePackage[left=2.5cm,right=2.5cm,top=2.5cm,bottom=2.5cm]{geometry}
\RequirePackage{amsmath,amssymb,bm}
\RequirePackage{graphicx}
\RequirePackage{booktabs,array,multirow,longtable}
\RequirePackage[font=small,labelsep=quad]{caption}
\RequirePackage{xcolor}
\RequirePackage{listings}
\RequirePackage{enumitem}
\RequirePackage[hidelinks]{hyperref}

% ---------- 字体设置（使用模板目录 fonts/ 下的字体） ----------
% 中文正文：宋体（Songti SC）；标题/强调：黑体（Heiti SC）
% 西文与数字：Times New Roman
% 若未携带 fonts/ 目录，可将下面设置替换为系统字体，例如：
%   \setCJKmainfont{SimSun} \setCJKsansfont{SimHei}
\setmainfont{Times New Roman}[
  Path = fonts/, Extension = .ttf,
  BoldFont = {Times New Roman Bold},
  ItalicFont = {Times New Roman Italic},
  BoldItalicFont = {Times New Roman Bold Italic},
]
\setCJKmainfont{SongtiSC}[
  Path = fonts/, Extension = .ttf,
  UprightFont = SongtiSC-Regular,
  BoldFont = SongtiSC-Bold,
  ItalicFont = SongtiSC-Regular,
  BoldItalicFont = SongtiSC-Bold,
]
\setCJKsansfont{HeitiSC}[
  Path = fonts/, Extension = .ttf,
  UprightFont = HeitiSC-Light,
  BoldFont = HeitiSC-Medium,
]
\setCJKmonofont{SongtiSC}[Path = fonts/, Extension = .ttf, UprightFont = SongtiSC-Regular]
\setCJKfamilyfont{zhsong}{SongtiSC}[Path = fonts/, Extension = .ttf, UprightFont = SongtiSC-Regular, BoldFont = SongtiSC-Bold]
\setCJKfamilyfont{zhei}{HeitiSC}[Path = fonts/, Extension = .ttf, UprightFont = HeitiSC-Light, BoldFont = HeitiSC-Medium]
\setCJKfamilyfont{zhkai}{SongtiSC}[Path = fonts/, Extension = .ttf, UprightFont = SongtiSC-Regular]

% ---------- 标题层级：一级四号黑体居中，二级小四黑体左对齐 ----------
\ctexset{
  section = {
    format = {\centering\heiti\zihao{4}},
    aftername = {\quad},
    beforeskip = {1.2ex plus 0.3ex},
    afterskip = {1.0ex plus 0.2ex},
  },
  subsection = {
    format = {\heiti\zihao{-4}},
    aftername = {\quad},
    beforeskip = {1.0ex plus 0.2ex},
    afterskip = {0.8ex plus 0.2ex},
  },
  subsubsection = {
    format = {\heiti\zihao{-4}},
    aftername = {\quad},
  },
}
\linespread{1.4}
\setlength{\parskip}{0.3ex}
\setlength{\emergencystretch}{3em}
% 规范：页码位于页脚中部，阿拉伯数字从摘要页 1 开始连续编号。
\pagestyle{plain}

% ---------- 草稿批注宏（定稿前必须全部删除或落实） ----------
\newcommand{\todonote}[1]{\textcolor{red}{【#1】}}

% ---------- 代码排版设置（附录） ----------
\lstset{
  language=Python,
  basicstyle=\ttfamily\zihao{-5},
  keywordstyle=\bfseries,
  commentstyle=\color{black!60},
  stringstyle=\color{black!60},
  columns=fullflexible,
  keepspaces=true,
  breaklines=true,
  breakatwhitespace=false,
  showstringspaces=false,
  numbers=left,
  numberstyle=\tiny\color{black!50},
  frame=single,
  framerule=0.3pt,
  rulecolor=\color{black!40},
  tabsize=4,
}

% ---------- 常用数学简写 ----------
\newcommand{\R}{\mathbb{R}}
\newcommand{\diff}{\,\mathrm{d}}