layout.sty

\usepackage[top=2cm, bottom=2cm, left=2cm, right=2cm]{geometry}
\usepackage{fancyhdr}
\usepackage{lastpage}
\usepackage{titling}
\usepackage[explicit]{titlesec}

\usepackage{pifont} % Pour la puce de Gineste
\usepackage{soul} % Pour souligner

\usepackage{dirtree} % Pour afficher des arbres de fichiers, cf. https://tug.ctan.org/macros/generic/dirtree/dirtree.pdf


\def\@maketitle{%
  \vspace{-1.5cm}%
  \begin{center}%
    \LARGE
    \underline{\underline{\thetitle\hspace{0.2em}: }}\\
    \SubTitle
  \end{center}%
  \par
  \vskip 1.5em}


\titleformat{\section}
{\normalfont\Large\bfseries\color{redd}}
{\thesection .}
{1em}
{#1}
[{\titlerule[0.9pt]}]

\titleformat{\subsection}
{\normalfont\bfseries\color{blued}}
{\thesubsection.}
{1em}
{#1}
[{\titlerule[0.7pt]}]

\titleformat{\subsubsection}
{\normalfont\color{blued}}
{\thesubsubsection.}
{1em}
{#1}
[{\titlerule[0.4pt]}]

\pagestyle{fancy}

\renewcommand\headrulewidth{1pt}
\fancyhead[L]{\Subject\hspace{0.4em}- \@title}
\fancyhead[R]{\thedate}


\renewcommand\footrulewidth{1pt}
\fancyfoot[L]{\theauthor}
\fancyfoot[R]{\Place}
\fancyfoot[C]{\thepage/\pageref{LastPage}}

\fancypagestyle{plain}{}