\usepackage{setspace}
\usepackage{enumitem}

\renewcommand\thesection{\Roman{section}}
\renewcommand\thesubsection{\arabic{subsection}}
\renewcommand\thesubsubsection{\alph{subsubsection}}

% ------------------------------------ %

\usepackage{titlesec}

\titleformat{\section}
{\LARGE\bfseries}
{\thesection. }
{0em}
{\setstretch{0.4}}

\titleformat{\subsection}
{\Large}
{\thesubsection. }
{0em}
{\setstretch{0.4}}

\titleformat{\subsubsection}
{}
{\thesubsubsection \,- }
{0em}
{\setstretch{0.4}}

\setlength{\parindent}{0em}

% ------------------------------------ %

\usepackage{fancyhdr}

\pagestyle{fancy}
\fancyhf{}
\setlength{\headheight}{14pt}
\lhead{\nouppercase{\leftmark}}
\rfoot{Page \thepage}

% ------------------------------------ %

\usepackage{dirtytalk}