\ProvidesPackage{di/heading}

\RequirePackage{titlesec}

% Add a counter to the label of the subsubsection
\setcounter{secnumdepth}{3}

% Modify the \chapter format
\titleformat{\chapter}
	{\LARGE\bf} 	% format
	{\thechapter.}	% label
	{6pt}			% horizontal separation between label and title body
	{}				% before code
	
\titlespacing*{\chapter}
	{0pt}
	{-\topskip} % correct space above chapter
	{0pt}

% Modify numberless chapter titles
% Is used solely for heading of distribution list, document history, table of contents etc.
\titleformat{name=\chapter, numberless}
	{\vspace{0.8cm}\Large\bf\filcenter}
	{}
	{0pt}
	{}
	[\vspace{3pt}]

% Modify the \section format
\titleformat{\section}
	{\vspace{5pt}\Large\bf}
	{\thesection.}
	{3pt}
	{}

\titlespacing*{\section}
	{0pt}
	{0pt}
	{0pt}

% Modify the \subsection format
\titleformat{\subsection}
	{\vspace{5pt}\large\bf}
	{\thesubsection.}
	{3pt}
	{}
	
\titlespacing*{\subsection}
	{0pt}
	{0pt}
	{0pt}

% Modify the \subsubsection format
\titleformat{\subsubsection}
	{\vspace{5pt}\large\bf}
	{\thesubsubsection.}
	{3pt}
	{}
	
\titlespacing*{\subsubsection}
	{0pt}
	{0pt}
	{0pt}