% Fonts, language and markup shared by all the variants.
% Load after \documentclass and \geometry.
\usepackage{iftex}
\ifPDFTeX
  \usepackage[OT1,LGR]{fontenc}
  \usepackage{gfsporson}
  \renewcommand\rmdefault{porson}
  \DeclareFontFamily{OT1}{porson}{}% Latin characters: Computer Modern
  \DeclareFontShape{OT1}{porson}{m}{n}{<->ssub*cmr/m/n}{}
  \DeclareFontShape{OT1}{porson}{b}{n}{<->ssub*cmr/bx/n}{}
  \newcommand\latin{\fontencoding{OT1}\fontfamily{cmr}\selectfont}
  % in LGR the ASCII ";" is the ano teleia; the question mark is another glyph
  \begingroup\lccode`~=`;\lowercase{\endgroup\def~{\texterotimatiko}}
  \AtBeginDocument{\catcode`;=\active}
\else
  \usepackage{fontspec}
  \setmainfont{GFS Porson}
  \newfontfamily\latin{Latin Modern Roman}
  \usepackage{newunicodechar}
  \newunicodechar{·}{\char"0387\relax}% ano teleia: the font's glyph
\fi
\usepackage[greek.ancient]{babel}
\raggedbottom
\setlength\emergencystretch{1.5em}

% Stephanus reference in the margin
\newcommand\st[1]{\leavevmode\marginpar{\footnotesize\latin\bfseries #1}}
% title page followed by a blank page
\newcommand\frontpage{%
  \thispagestyle{empty}\vspace*{\stretch{1}}%
  \begin{center}\LARGE ΠΛΑΤΩΝΟΣ\\ ΚΡΙΤΩΝ\end{center}%
  \vspace*{\stretch{2}}\newpage
  \thispagestyle{empty}\null\newpage}
% title of the dialogue and its characters
\newcommand\heading{%
  \begin{center}\Large ΚΡΙΤΩΝ\\[1ex]\normalsize ΣΩΚΡΑΤΗΣ\quad ΚΡΙΤΩΝ\end{center}}