% mod1.sty
\renewcommand{\section}
{\@startsection{section}{1}{\z@}
  {-3ex plus -1ex minus-.2ex}{2ex plus.2ex}
  {\centering\normalfont\scshape}}

\renewcommand{\subsection}
{\@startsection{subsection}{2}{\z@}
  {-2ex plus -1ex minus-.2ex}{2ex plus.2ex}
  {\centering\normalfont\itshape}}