\documentclass[A4,12pt,twoside]{book}
\usepackage{amd}
% %--------------------------------------------------------------------------
% % General Setting
% %--------------------------------------------------------------------------
\graphicspath{{Images/}{../Images/}} %Path of figures
\setkeys{Gin}{width=0.85\textwidth} %Size of figures
\setlength{\cftbeforechapskip}{3pt} %space between items in toc
\setlength{\parindent}{0.5cm} % Idk
\input{theorems.tex} % Theorems styles and colors
\usepackage[english]{babel} %Language
\setlist[itemize]{itemsep=5pt} % Adjust the length as needed
\setlist[enumerate]{itemsep=5pt} % Adjust the length as needed
% \usepackage{lmodern} % Latin Modern font
% \usepackage{newtxtext,newtxmath}
% %--------------------------------------------------------------------------
% % General Informations
% %--------------------------------------------------------------------------
\newcommand{\BigTitle}{
A MATHEMATICAL TEMPLATE
}
\newcommand{\LittleTitle}{
For Mathematical Peoples
}
\begin{document}
% %--------------------------------------------------------------------------
% % First pages
% %--------------------------------------------------------------------------
\newgeometry{top=8cm,bottom=.5in,left=2cm,right=2cm}
\subfile{files/0.0.0.titlepage}
\restoregeometry
\subfile{files/0.Preface}
\subfile{files/0.zommaire}
% %--------------------------------------------------------------------------
% % Core of the document
% %--------------------------------------------------------------------------
\part{First part}
\subfile{files/0.0.testchap}
\subfile{files/0.0.testchap}
\subfile{files/0.0.testchap}
\part{Second part}
\subfile{files/0.0.testchap}
\subfile{files/0.0.testchap}
\subfile{files/0.0.testchap}
\part{Third part}
\subfile{files/0.0.testchap}
\subfile{files/0.0.testchap}
\subfile{files/0.0.testchap}
% %--------------------------------------------------------------------------
% % Bibliographie
% %--------------------------------------------------------------------------
\nocite{*} % to cite evey things, else cite each on using : \cite{ifrs17}.
\printbibliography %to print bibliographie
\end{document}