standardsetup.sty

\usepackage{ifluatex}

\ifluatex
    \usepackage{polyglossia}
    \setmainlanguage{english}
    \usepackage{fontspec}
    \setmainfont{linuxlibertine}

    \usepackage[]{unicode-math}
    % \setmathfont{linuxlibertine}

\else
    \usepackage[utf8]{inputenc}
    \usepackage[T1]{fontenc}
    \usepackage{libertine}
    \usepackage[english]{babel}
\fi


\usepackage{color}
\definecolor{darkred}{rgb}{0.5,0,0}
\definecolor{darkorange}{rgb}{1,0.549019607843137,0}
\definecolor{lightblue}{rgb}{0.247059,0.407843,1}

\usepackage{graphicx}

\usepackage{booktabs}             % table decorations

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{mathrsfs}             % calligraphie

\usepackage{siunitx}
\newcommand\unit[2]{\SI{#1}{#2}}


% powerful graphics package
\usepackage{tikz}
\usetikzlibrary{plotmarks,patterns,calc,decorations.markings,arrows,
                decorations.pathmorphing,intersections}
\tikzset{snake it/.style={decorate, decoration=snake}}

% layer on top of tikz to efficiently draw plots
\usepackage{pgfplots}
\usepgflibrary{shapes}
\usepgfplotslibrary{groupplots}
\pgfplotsset{compat=newest}

\newlength\figureheight
\newlength\figurewidth
\setlength\figureheight{8cm}
\setlength\figurewidth{10cm}


% \usepackage{pgffor}               % for-loop

% \usepackage{pdfpages}

% \usepackage[percent]{overpic}     % draw text atop of pictures


% this `put` can be used anywhere
\def\Put(#1,#2)#3{\leavevmode\makebox(0,0){\put(#1,#2){#3}}}


% ISO conform date format
\def\mydate{\leavevmode\hbox{\the\year-\twodigits\month-\twodigits\day}}
\def\twodigits#1{\ifnum#1<10 0\fi\the#1}