\documentclass{scrreprt}
% European typography -> KOMA-Script documentclasses 
% classes are scrbook, scrreprt, scrartcl, scrlettr2
% a4paper is the default for all KOMA-Script classes

\KOMAoptions{
paper=portrait, % portrait (default), or landscape
BCOR=0mm, % no binding correction for single pages
% default font size 11pt, for scrlettr2 it is 12pt
fontsize=12pt, % larger for academic papers (12pt)
headsepline=true,  % separator line for the header
footsepline=true,  % separator line for the footer
}
\usepackage{scrhack}  % fixes problems with listings

% BCOR in KOMA-Scripts not with the geometry package
% KOMA-Script uses package typearea for page layout, 
% automatically loaded. DIV = number of page columns
% "DIV" defaults for A4 are 10pt:8, 11pt:10, 12pt:12 
% default type area and margins (A4 and BCOR=0), mm: 
% 10pt DIV  8, 131.25 x 185.63 top 37.13 inner 26.25  
% 11pt DIV 10, 147.00 x 207.90 top 29.70 inner 21.00  
% 12pt DIV 12, 157.50 x 222.75 top 24.75 inner 17.50  

% with KOMA-Script: use geometry only when necessary 
% \usepackage[margin=2cm,includefoot]{geometry}
% documentclass options a4paper,portrait -> geometry
% paper = total body (printable area) + margins
% margin = 2 cm from each edge of the paper
% includefoot includes foot into total body 

\usepackage[english]{babel} % american english text
% \usepackage[ngerman]{babel} % german, new orthogr.
\usepackage[utf8]{inputenc} % input UTF-8 characters
\usepackage[T1]{fontenc} % T1 font encoding, not OT1
\usepackage{lmodern} % use the Latin Modern fonts

\usepackage[sortlocale=auto,sorting=nyt, % sorting
style=numeric-comp]{biblatex} % or authoryear-comp
\addbibresource{lit_240112.bib}
\usepackage{csquotes,xpatch}

\usepackage{xcolor}   % package for using colors
\usepackage{graphicx} % package for images, graphics
\usepackage{makeidx}  % standard package for indexes
\makeindex % when compiling, make index file ___.idx

% package listings, only to typeset code of programs
\usepackage{listings} % package for code integration
\lstset{literate= % define umlauts and ß in listings
	{Ä}{{\"A}}1 {Ö}{{\"O}}1 {Ü}{{\"U}}1 
	{ä}{{\"a}}1 {ö}{{\"o}}1 {ü}{{\"u}}1
	{ß}{{\ss}}1           
}
\lstset{
language=Python, % programming language of the code
basicstyle=\ttfamily, % general code style: tt font
tabsize=4, % replace each tab with our spaces
commentstyle=\color{blue}, % color comments blue
keywordstyle=\color{green}, % color keywords green
numbers=left, % line numbers left
xleftmargin=8mm, % left margin (for line numbers)
xrightmargin=3mm, % right margin (smaller frame)
numberstyle=\footnotesize\ttfamily, % number style
showstringspaces=false, % normal spaces in strings
frame=trbl,  % frame on top, right, left and bottom
frameround=tttt % rounded corners in the frame
}

% \pagestyle{empty} % header and footer are empty
\pagestyle{plain} % footer contains page number
% warning: the handling of page numbers is difficult

\begin{document}
	
%\iffalse % if not commented out: do not compile this
% --------------------------------------------------
\title{Rolling Stones}
\subtitle{A report on petrokinesis}
\author{Sisy Phos}
\date{\today}
\maketitle % print the title page with above items

\tableofcontents % generate the table of contents
% --------------------------------------------------
%\fi

%\iffalse % if not commented out: do not compile this
% --------------------------------------------------
\chapter{Reports shoud have chapters}

\section{Title of first section of first chapter}
Something \emph{important} and a \textbf{bold} word.

% a floating environment (float) must be on one page
% floats (figures, tables): positioned automatically  
\begin{figure}[h] % place image (approximately) here 
\centering % horizontal image position in the middle
\def\fig{~/image/erdbev.jpg} % path to image file
\IfFileExists{\fig} % check, if image file exists
   { \includegraphics[scale=0.3]{\fig} }
   { \textcolor{red}{Warning: missing image file} }
\caption{This is a figure caption below the image.}
\end{figure}

Note: the first line of a new paragraph is indented.
The word tetrapod\index{tetrapod} will be found in 
the index. Whitespace between
        words           is reduced to one space.
% key word in {} -> index, with actual page number 
% --------------------------------------------------
%\fi

% \iffalse % if not commented out: do not compile this
% --------------------------------------------------
\chapter{Here comes another chapter}

\section{Title of first section of second chapter}

\subsection{Crime doesn't pay}

\subsubsection{Piracy}
Pirates don't have it easy! \cite{hook2013a}.

My Python program that greets the world:
\par\medskip % new paragraph, with vertical spacing
\begin{lstlisting}
#!/usr/bin/env python3
print("Hello, world!")
\end{lstlisting}

% --------------------------------------------------
% \fi

%\iffalse % if not commented out: do not compile this
% --------------------------------------------------
\printbibliography % print the bibliography here
\printindex % print the index here (using ---.idn)
% --------------------------------------------------
%\fi

\end{document}