\newcommand{\nl}{\newline\indent}
\usepackage{tcolorbox}
\usepackage{etoolbox}

% paragraph indentation
\usepackage{parskip}
%\setlength{\parfill}{0pt}
\setlength{\parindent}{15pt}

% to add subtitle to \maketitle
\makeatletter
\providecommand{\subtitle}[1]{
  \apptocmd{\@title}{\par {\large #1 \par}}{}{}
}
\makeatother

\usepackage{graphicx}
\graphicspath{{img/}}
\usepackage{pdfpages}

% for Japanese chars
\usepackage{xeCJK}
\setCJKmainfont[BoldFont=STHeiti,ItalicFont=STKaiti]{STSong}

% for itemization, other symbol
\renewcommand{\labelitemi}{$\circ$}
% labelitemii, iii, iv, ... kan ook

% for index
\usepackage{imakeidx}
\makeindex[title=Appendix,columns=2,intoc,options= -s indexstyle.ist]