template.tex

\RequirePackage{amsthm}
\documentclass[
    [#- if options.reference_style == "default"   -#] default      [#- endif -#]
    [#- if options.reference_style == "apa"       -#] sn-apa       [#- endif -#]
    [#- if options.reference_style == "aps"       -#] sn-aps       [#- endif -#]
    [#- if options.reference_style == "basic"     -#] sn-basic     [#- endif -#]
    [#- if options.reference_style == "chicago"   -#] sn-chicago   [#- endif -#]
    [#- if options.reference_style == "nature"    -#] sn-nature    [#- endif -#]
    [#- if options.reference_style == "mathphys"  -#] sn-mathphys  [#- endif -#]
    [#- if options.reference_style == "vancouver" -#] sn-vancouver [#- endif -#]
    [#- if options.pdf_latex -#]                     , pdflatex    [#- endif -#]
    [#- if options.referee -#]                       , referee     [#- endif -#]
    [#- if options.numbered_referencing -#]          , Numbered    [#- endif -#]
    [#- if options.formatting == "twocolumn" -#]     , iicol       [#- endif -#]
    ]{sn-jnl}


\usepackage{graphicx}%
\usepackage{multirow}%
\usepackage[mathlines]{lineno}
\usepackage{amsmath,amssymb,amsfonts}%
\usepackage{amsthm}
\usepackage{mathrsfs}
\usepackage[title]{appendix}
\usepackage{xcolor}
\usepackage{textcomp}
\usepackage{manyfoot}
\usepackage{booktabs}
\usepackage{algorithm}
\usepackage{algorithmicx}
\usepackage{algpseudocode}
\usepackage{listings}
\usepackage{etoolbox}


% line numbering of equation lines using amsmath (https://tex.stackexchange.com/questions/461186/how-to-use-lineno-with-amsmath-align)
%% Patch 'normal' math environments:
\newcommand*\linenomathpatch[1]{%
  \cspreto{#1}{\linenomath}%
  \cspreto{#1*}{\linenomath}%
  \csappto{end#1}{\endlinenomath}%
  \csappto{end#1*}{\endlinenomath}%
}
%% Patch AMS math environments:
\newcommand*\linenomathpatchAMS[1]{%
  \cspreto{#1}{\linenomathAMS}%
  \cspreto{#1*}{\linenomathAMS}%
  \csappto{end#1}{\endlinenomath}%
  \csappto{end#1*}{\endlinenomath}%
}

%% Definition of \linenomathAMS depends on whether the mathlines option is provided
\expandafter\ifx\linenomath\linenomathWithnumbers
  \let\linenomathAMS\linenomathWithnumbers
  %% The following line gets rid of an extra line numbers at the bottom:
  \patchcmd\linenomathAMS{\advance\postdisplaypenalty\linenopenalty}{}{}{}
\else
  \let\linenomathAMS\linenomathNonumbers
\fi

\linenomathpatch{equation}
\linenomathpatchAMS{gather}
\linenomathpatchAMS{multline}
\linenomathpatchAMS{align}
\linenomathpatchAMS{alignat}
\linenomathpatchAMS{flalign}

% Disable line numbering during measurement step of multline
\makeatletter
\patchcmd{\mmeasure@}{\measuring@true}{
  \measuring@true
  \ifnum-\linenopenaltypar>\interdisplaylinepenalty
    \advance\interdisplaylinepenalty-\linenopenalty
  \fi
  }{}{}
\makeatother



[- IMPORTS -]

\raggedbottom
[#- if options.unnumbered_headings #]
\unnumbered   
[# endif -#]

[#- if options.theorem_style == "one" #]
\theoremstyle{thmstyleone}
[# endif -#]
[#- if options.theorem_style == "two" #]
\theoremstyle{thmstyletwo}
[# endif -#]
[#- if options.theorem_style == "three" #]
\theoremstyle{thmstylethree}
[# endif -#]
[#- if options.theorem_style != "none" #]
[#- if options.theorem_sectionwise_numbering #]
\newtheorem{theorem}{Theorem}[section]
[# else #]
\newtheorem{theorem}{Theorem}
[# endif -#]

[#- if options.proposition_by_theorem_numbering #]
\newtheorem{proposition}[theorem]{Proposition}
[# else #]
\newtheorem{proposition}{Proposition}
[# endif -#]
\newtheorem{example}{Example}
\newtheorem{remark}{Remark}
\newtheorem{definition}{Definition}
[# endif -#]

[#- if options.line_numbers -#] 
\linenumbers
[#- endif -#]

\begin{document}

\title[[-doc.short_title-]]{[-doc.title-]}

[#- for author in doc.authors #]
[#- if author.corresponding #]
\author*[[- author.affiliations | join(',', 'index') -]]{
    [#- if author.given_name #]\fnm{[-author.given_name-]} [# endif -#]
    [#- if author.surname #]   \sur{[-author.surname-]}    [# endif -#]
    [#- if author.email #]     
        \email{[-author.email-]}
    [# else #]
        \nomail    
    [# endif -#]
    } 
[# else #]
\author[[- author.affiliations | join(',', 'index') -]]{
    [#- if author.given_name #]\fnm{[-author.given_name-]} [# endif -#]
    [#- if author.surname #]   \sur{[-author.surname-]}    [# endif -#]
    [#- if author.email #] 
        \email{[-author.email-]}
    [# else #]
        \nomail
    [# endif -#]
    }     
[# endif -#]
[# endfor -#]

[#- for affiliation in doc.affiliations #]
\affil[[-affiliation.index-]]{
        \orgdiv{[- affiliation.value.department -]}
        \orgname{[-  affiliation.value.institution -]}
        \orgname{[- affiliation.value.name -]}
        \orgaddress{
            \street{[- affiliation.value.address -]}
            \city{[- affiliation.value.city -]}
            \postcode{[- affiliation.valuepostal_code -]}
            \state{[- affiliation.value.state -]}
            \country{[- affiliation.value.country-]}}}
[# endfor -#]

[#- if parts.abstract -#]
\abstract{
[-parts.abstract-]
}
[#- endif -#]

[#- if doc.keywords #]
\keywords{[- doc.keywords | join(", ") -]}
[# endif -#]


\maketitle

[-CONTENT-]


\backmatter

[#- if parts.supplementary_information #]
\bmhead{Supplementary information}
[-parts.supplementary_information-]
[# endif -#]


[#- if parts.acknowledgments #]
\bmhead{Acknowledgments}
[-parts.acknowledgments-]
[# endif -#]


[#- if parts.declarations #]
\section*{Declarations}
[-parts.declarations-]
[# endif -#]


[#- if parts.appendix #]
\begin{appendices}
[-parts.appendix-]
\end{appendices}
[# endif -#]


[#- if doc.bibliography #]
\bibliography{[- doc.bibliography | join(", ") -]}
[# endif -#]

\end{document}