gistfile1.tex

\usepackage{appendix}
\makeatletter
\newcommand\appendix@chapter[1]{
  \refstepcounter{chapter}
	\orig@chapter*{
		\vspace*{-72pt}
		\subsectionsize\bfseries Appendix \@Alph\c@chapter: #1
		\vspace*{-36pt}
	}
	\addcontentsline{toc}{chapter}{Appendix \@Alph\c@chapter: #1}
}
\let\orig@chapter\chapter
\g@addto@macro\appendix{\let\chapter\appendix@chapter}
\makeatother