Custom LaTeX style used to create my lectures notes.

notes.sty

\NeedsTeXFormat{LaTeX2e}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Package name and information %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\ProvidesPackage{notes}[2020/01/14 Bizzozzéro Nicolas custom LaTeX style]


%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Most used packages %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage[utf8]{inputenc}       % Encoding input
\usepackage[T1]{fontenc}          % Encoding font
\usepackage[hidelinks]{hyperref}
\usepackage[french]{babel}        % Language used
\usepackage[margin=3cm]{geometry} % Margin 

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{appendix}
\usepackage{array}
\usepackage{bbm}
\usepackage[style=alphabetic,sorting=none,natbib=true]{biblatex}
\usepackage{booktabs}
\usepackage[makeroom]{cancel}
\usepackage{caption}
\usepackage{catchfile}
\usepackage{color}
\usepackage{csquotes}
\usepackage{enumitem}
\usepackage{fancyvrb}
\usepackage{float}
\usepackage{fontawesome}
% \usepackage{fourier}            % Warning: this package change the document's font
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{inconsolata}
\usepackage{kbordermatrix}
\usepackage{listings}
\usepackage{longtable}
\usepackage{lstautogobble}
\usepackage{mathtools}
\usepackage[outputdir=bin]{minted}
\usepackage{multicol}
\usepackage{multirow}
\usepackage{parskip}
\usepackage{pgf}
\usepackage{qtree}
\usepackage{regexpatch}
\usepackage{relsize}
\usepackage{rotating}
\usepackage{stmaryrd}
\usepackage{subcaption}
\usepackage{tabularx}
\usepackage[colorinlistoftodos,prependcaption]{todonotes}
\usepackage{verbatim}
\usepackage{wasysym}
\usepackage{wrapfig}
\usepackage{xcolor}
\usepackage{xstring}


%%% Tikz configuration
\usepackage{tikz}
\usepackage[framemethod=tikz]{mdframed}
\usetikzlibrary{arrows, automata, mindmap, positioning}
\def\checkmark{\tikz\fill[scale=0.4](0,.35) -- (.25,0) -- (1,.7) -- (.25,.15) -- cycle;}

%%% Algorithm display
\usepackage[ruled,vlined,linesnumbered,lined,boxed,commentsnumbered]{algorithm2e}

%%% Item symbol
\AtBeginDocument{\def\labelitemi{$\bullet$}}

%%% todonotes
%% Making todonotes appear inline
\makeatletter
\xpatchcmd{\@todo}{\setkeys{todonotes}{#1}}{\setkeys{todonotes}{inline,#1}}{}{}
\makeatother

%%% tabularx
%% New centered column-type
\newcolumntype{Y}{>{\centering\arraybackslash}X}


%%%%%%%%%%%%%%%%%%%%
%%% Bibliography %%%
%%%%%%%%%%%%%%%%%%%%

\addbibresource{main.bib}


%%%%%%%%%%%%%
%%% Fonts %%%
%%%%%%%%%%%%%

%%% Default Math-Mode font
\DeclareMathAlphabet{\mathcal}{OMS}{cmsy}{m}{n}


%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Section name format %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%
\setcounter{secnumdepth}{50}
\setcounter{tocdepth}{50}
\renewcommand{\thesection}{\arabic{section}}
\renewcommand{\thesubsection}{\arabic{section}.\arabic{subsection}}
\renewcommand{\thesubsubsection}{\arabic{section}.\arabic{subsection}.\arabic{subsubsection}}
\renewcommand{\thefigure}{\arabic{figure}}
\renewcommand{\thetable}{\arabic{table}}


%%%%%%%%%%%%%%%%%%%%
%%% Environments %%%
%%%%%%%%%%%%%%%%%%%%

%%% lstlistings
\lstset{
    language=python,
    backgroundcolor=\color{gray!10},
    basicstyle=\ttfamily\small,
    breakatwhitespace=true,
    breaklines=true,
    commentstyle=\color[HTML]{556b2f},
    escapeinside={\%*}{*)},
    extendedchars=true,
    frame=single,
    framexbottommargin=2pt,
    framextopmargin=2pt,
    inputencoding=utf8,
    keywordstyle=\color{blue},
    numbers=none,
    numberstyle=\footnotesize,
    rulecolor=\color{black!30},
    stringstyle=\color{red},
    tabsize=4,
    title=\lstname,
    literate={á}{{\'a}}1 {ã}{{\~a}}1 {é}{{\'e}}1 {è}{{\`e}}1 {ê}{{\^e}}1 {À}{{\`A}}1 {à}{{\`a}}1 {â}{{\^a}}1 {'}{{'}}1 {ç}{{\c{c}}}1 {`}{{`}}1
}

%%% Proof
\newenvironment{myproof}[1][\proofname]{\proof[#1]\mbox{}\\*}{\endproof}

%%% Questions / Answers (To create a quizz, for example)
\newenvironment{questions}{\begin{enumerate}[label=$\bullet$]\bfseries}
                          {\end{enumerate}}
\newenvironment{answer}{\par\par\par\normalfont}{}

%%
% Enumerate conditions under an equation.
%
% Usage :
% \begin{conditions}
%     A & :           & notional permeability factor \\
%     B & \sim        & number of waves \\
%     C & \rightarrow & damage level
% \end{conditions}
% 
% Source :
% https://tex.stackexchange.com/a/225574
%%
\newenvironment{conditions}[1][where:]
  {\begin{minipage}{\textwidth}
   \vspace*{-.5\belowdisplayskip}%
   \linespread{1}\selectfont #1 \begin{tabular}[t]{>{$}l<{$} @{${}:{}$} l}}
  {\end{tabular}\end{minipage}\\[\belowdisplayskip]}

\newenvironment{conditions*}[1][where:]
  {\begin{minipage}{\textwidth}
   \vspace*{-.5\belowdisplayskip}%
   \linespread{1}\selectfont #1 \begin{tabular}[t]{>{$}l<{$} @{}>{${}}c<{{}$}@{} l}}
  {\end{tabular}\end{minipage}\\[\belowdisplayskip]}


%%
% Provides an itemized environment for defining words.
%
% Usage :
% \begin{worddefs}
%   \item[Word1.] This word is a word.
%   \item[Word2.] This word is also totally a word but with a longer definition than its predecessor.
%   Its definition also spans over multiple lines.
%   \item[BigAndLongWordThatIsExtraLong and with spaces.] Is it a word ? Yes it is. 
% \end{worddefs}
%%
\newlist{worddefs}{description}{1}
\setlist[worddefs]{font=\sffamily\bfseries, labelindent=\parindent, leftmargin=6em, style=sameline}


%%%%%%%%%%%%%%%%
%%% Commands %%%
%%%%%%%%%%%%%%%%

%%% Make tab's cells bold and centered. To use in every header cell
\newcommand*{\thead}[1]{%
\multicolumn{1}{c}{\bfseries\begin{tabular}{@{}c@{}}#1\end{tabular}}}

%%% Put annotations under or over an equation
\newcommand{\overAnnotation}[2]{\overset{\mathclap{\substack{#2\\ \Big\downarrow}}}{#1}}
\newcommand{\underAnnotation}[2]{\underset{\mathclap{\substack{\Big\uparrow\\ #2}}}{#1}}

%%% Proper mathematic syntax to define a function and its domains
\newcommand{\functionDefinition}[5]{
    \begin{align*}
        #1 \colon #2 & \longrightarrow #3 \\
                  #4 & \longmapsto #5
    \end{align*}
}

%%% Derivative notation
\newcommand{\derivative}[3]{\frac{\partial^{^{#3}}\! #1}{\partial#2^{^{#3}}}}

%%% Highlight text needing updates
\newcommand{\TODO}[1]{
    \textbf{\textcolor{red}{
        \LARGE{\underline{TODO:}}
        \url{#1}
    }}
    \PackageWarning{TODO:}{#1!}
}

%%
% Output an aligned left bracket with 3 columns.
%
% Parameters :
% #1 : Prior
% #2 : content
%
% Exemple :
% \begin{equation}
% \equationLeftBracket{f =}{
%     a & = & y_1 \\
%     b & \leq & y_2 \\
%     c & \geq & y_3
% }
% \end{equation}
%%
\newcommand{\equationLeftBracket}[2]{
#1 \left\{
       \begin{array}{rcl}
       #2
       \end{array}
   \right.
}

%%
% Set the \commit and \branch variables, containing current git commit hash
% and git branch of the .git directory at the same level as this file.
%
% Source:
% https://tex.stackexchange.com/a/455397
%%
% \CatchFileDef{\headfull}{.git/HEAD.}{}
% \StrGobbleRight{\headfull}{1}[\head]
% \StrBehind[2]{\head}{/}[\branch]
% \CatchFileDef{\commit}{.git/refs/heads/\branch.}{}

%%
% Create new column types which set a fixed size for a column.
%
% Parameters :
% #1 : Size of the column
%
% Exemple :
% \begin{table}[ht]
%   \begin{center}
%       \begin{tabular}{L{4cm} | R{4cm}}  % <- Used here
%           a & b
%       \end{tabular}
%   \end{center}
% \end{table}
%%
\newcolumntype{L}[1]{>{\raggedright\let\newline\\\arraybackslash\hspace{0pt}}m{#1}}
\newcolumntype{C}[1]{>{\centering\let\newline\\\arraybackslash\hspace{0pt}}m{#1}}
\newcolumntype{R}[1]{>{\raggedleft\let\newline\\\arraybackslash\hspace{0pt}}m{#1}}


%%%%%%%%%%%%%%
%%% Macros %%%
%%%%%%%%%%%%%%

%%
% Macro defining an augmented matrix.
%
% Usage :
%    \begin{pmatrix}[cc|c]
%        1 & 2 & 3\\
%        4 & 5 & 6
%    \end{pmatrix}
%% 
\makeatletter
\renewcommand*\env@matrix[1][*\c@MaxMatrixCols c]{%
  \hskip -\arraycolsep
  \let\@ifnextchar\new@ifnextchar
  \array{#1}}
\makeatother


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Operators & Delimiters %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%% Argmax and Argmin maths operators 
\DeclareMathOperator*{\argmax}{\arg\!\max}
\DeclareMathOperator*{\argmin}{\arg\!\min}

%%% Ceil and Floor delimiters paired
\DeclarePairedDelimiter{\ceil}{\lceil}{\rceil}
\DeclarePairedDelimiter{\floor}{\lfloor}{\rfloor}


%%%%%%%%%%%%%%%%%%%%
%%% Tikz figures %%%
%%%%%%%%%%%%%%%%%%%%

%%
% Add the \info command, adding an info box used as leafs in mindmaps.
%%
\newcommand*{\info}[4][16.3]{%
  \node [ annotation, #3, scale=0.65, text width = #1em,
          inner sep = 2mm ] at (#2) {%
  \list{$\bullet$}{\topsep=0pt\itemsep=0pt\parsep=0pt
    \parskip=0pt\labelwidth=8pt\leftmargin=8pt
    \itemindent=0pt\labelsep=2pt}%
    #4
  \endlist
  };
}


%%%%%%%%%%%%%%%
%%% Symbols %%%
%%%%%%%%%%%%%%%

%%% Independence symbol
\newcommand{\independent}{\mathrel{\text{\scalebox{1.07}{$\perp\mkern-10mu\perp$}}}}

%%% Variance's function symbol
\newcommand{\Var}{\mathcal{V}\text{ar}}

%%%% Covariance's function symbol
\newcommand{\Cov}{\mathcal{C}\text{ov}}

%%% Correlation's function symbol
\newcommand{\Corr}{\mathcal{C}\text{orr}}

%%% Contradiction lighting symbol
\newcommand{\contradiction}{\lightning}

%%% Slice the page with an horizontal line
\newcommand{\horizontalLine}{\rule{\linewidth}{0.5mm}}

%%
% Proof symbol, QED, empty square
%%
\makeatletter
\DeclareRobustCommand{\qed}{%
  \ifmmode
    \eqno \def\@badmath{$$}%$$
    \let\eqno\relax \let\leqno\relax \let\veqno\relax
    \hbox{\openbox}%
  \else
    \leavevmode\unskip\penalty9999 \hbox{}\nobreak\hfill
    \quad\hbox{\openbox}%
  \fi
}
\makeatother

%%% Integral differential symbol
\newcommand{\diff}{\mathop{}\!d}


\endinput

If you want to use it, import this document in your directory then append the following line to your .tex file :

\usepackage{notes}

Here's a .tex template demonstrating a complete usage :

\documentclass{book}
\usepackage{notes}


\author{Author}
\title{Title}


\begin{document}
\maketitle
\tableofcontents


\chapter{Chapter 1}

\chapter{Chapter 2}

\chapter{Chapter 3}


\printbibliography


\appendix
\appendixpage
\addappheadtotoc


\section{Appendix 1}

\section{Appendix 2}


\end{document}