%% fang-journal.cls — Asia-Pacific Institute of Advanced Studies Publishing Center
%% Manuscript class (Elsevier-style), v1.1 2026
\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{fang-journal}[2026/01/01 v1.1 APAASpress Publishing Center manuscript class]

\LoadClass[11pt,a4paper]{article}

\RequirePackage[top=2.5cm,bottom=2.5cm,left=2.5cm,right=2.5cm]{geometry}
\RequirePackage{times}
\RequirePackage{graphicx}
\RequirePackage{amsmath,amssymb}
\RequirePackage{authblk}
\RequirePackage{abstract}
\RequirePackage[numbers,sort&compress]{natbib}
\RequirePackage{titlesec}
\RequirePackage{fancyhdr}
\RequirePackage{xcolor}
\RequirePackage[colorlinks=true,linkcolor=blue,citecolor=blue,urlcolor=blue]{hyperref}
\RequirePackage{setspace}
\RequirePackage{booktabs}
\RequirePackage{microtype}

%% ── Brand colours ──────────────────────────────────────────────────────────
\definecolor{apiasteal}{RGB}{26,39,68}    % navy
\definecolor{apiasgold}{RGB}{201,168,76}  % gold

%% ── Header / footer ────────────────────────────────────────────────────────
\pagestyle{fancy}
\fancyhf{}
\fancyhead[L]{\small\color{apiasteal}\textit{Asia-Pacific Institute of Advanced Studies Publishing Center}}
\fancyhead[R]{\small\thepage}
\fancyfoot[C]{\small\color{gray}\textit{Submitted manuscript — confidential review copy}}
\renewcommand{\headrulewidth}{0.6pt}
\renewcommand{\footrulewidth}{0.0pt}

%% ── Section formatting ─────────────────────────────────────────────────────
\titleformat{\section}
  {\large\bfseries\color{apiasteal}}{\thesection.}{0.5em}{}[\titlerule]
\titleformat{\subsection}
  {\normalsize\bfseries\color{apiasteal}}{\thesubsection.}{0.5em}{}
\titleformat{\subsubsection}
  {\normalsize\itshape\color{apiasteal}}{\thesubsubsection.}{0.5em}{}

%% ── Logo + title block ─────────────────────────────────────────────────────
\renewcommand{\maketitle}{%
  \thispagestyle{plain}%
  \begin{center}%
    %% Logo (included from logo.png in same directory)
    \IfFileExists{logo.png}{%
      \includegraphics[height=1.8cm]{logo.png}\par\vspace{0.6em}%
    }{%
      %% Fallback text-only header if logo.png is missing
      {\color{apiasteal}\rule{\linewidth}{1.5pt}}\par\vspace{0.3em}
      {\large\bfseries\color{apiasteal}Asia-Pacific Institute of Advanced Studies Publishing Center}\par
      {\color{apiasgold}\rule{\linewidth}{1pt}}\par\vspace{0.3em}%
    }%
    {\color{apiasgold}\rule{0.6\linewidth}{0.6pt}}\par\vspace{1em}%
    %% Paper title
    {\LARGE\bfseries\color{apiasteal}\@title\par}\vspace{0.8em}%
    %% Authors
    {\large\@author\par}\vspace{0.4em}%
    {\color{apiasteal}\rule{0.4\linewidth}{0.4pt}}\par\vspace{0.5em}%
  \end{center}%
}

%% ── Plain page style (first page) ──────────────────────────────────────────
\fancypagestyle{plain}{%
  \fancyhf{}%
  \fancyfoot[C]{\small\thepage}%
  \renewcommand{\headrulewidth}{0pt}%
}

%% ── Abstract styling ────────────────────────────────────────────────────────
\renewcommand{\abstractnamefont}{\bfseries\color{apiasteal}}
\renewcommand{\abstracttextfont}{\small\itshape}
\setlength{\absleftindent}{1cm}
\setlength{\absrightindent}{1cm}

%% ── Keywords command ────────────────────────────────────────────────────────
\newcommand{\keywords}[1]{%
  \par\vspace{0.4em}\noindent%
  \textbf{\color{apiasteal}Keywords:}\enspace\textit{#1}\par%
  \vspace{0.6em}{\color{apiasgold}\rule{\linewidth}{0.4pt}}\vspace{0.6em}%
}

%% ── Manuscript info command ─────────────────────────────────────────────────
%% Usage: \received{2026-07-01}  (optional, printed below keyword line)
\newcommand{\received}[1]{\def\@received{#1}}
\newcommand{\corrauthor}[1]{\def\@corrauthor{#1}}

%% ── Line spacing ────────────────────────────────────────────────────────────
\onehalfspacing

\endinput