Btukfyl

I have a problem with the background of my beamer slides. When I compile it on my PC (Windows 7, TeXLive 2015) I get the following background:

But when I compile it on my MacBook (Mojave, TeXLive 2018) I get the following background:

How can I fix it?

documentclass[red]{beamer}

beamertemplateshadingbackground{red!70}{yellow!85}



usepackage{verbatim}

mode<article> % only for the article version



{

  usepackage{fullpage}

  usepackage[bookmarks=false]{hyperref}

  }

mode<presentation>

{

  setbeamertemplate{background canvas}[vertical shading][bottom=red!10,top=blue!10]

  usetheme

  {Darmstadt}

   useoutertheme[height=0pt,width=2cm,left,]{sidebar}

setbeamerfont{section in sidebar}{size=fontsize{8.7}{8.6}selectfont}

setbeamerfont{subsection in sidebar}{size=fontsize{5.7}{6.7}selectfont}

useinnertheme{circles}

}



setbeamertemplate{footline}[text line]{

  hbox{%

    begin{beamercolorbox}[wd=3.7paperwidth,ht=2.25ex,dp=1ex,left]{date in head/foot}%

      usebeamerfont{date in head/foot}

      hspace*{1ex} insertframenumber{} / inserttotalframenumber

      hspace*{5ex} insertshortdate

    end{beamercolorbox}%

    }

} % makes the footer EMPTY





setbeamercovered{transparent=10}



makeatletter

TeXXeTstate=1

deffarsitext#1{begingroupbeginRfarsifont#1endRendgroup}

setbeamertemplate{frametitle}{

    ifbeamercolorempty[bg]{frametitle}{}{nointerlineskip}

    @tempdima=textwidth

    advance@tempdima bybeamer@leftmargin

    advance@tempdima bybeamer@rightmargin

    vspace*{0.055cm}

    begin{beamercolorbox}[sep=0.3cm,center,wd=the@tempdima]{frametitle}

        usebeamerfont{frametitle}

        vbox{}vskip-1ex

        if@tempswaelsecsname beamer@ftecenterendcsnamefi

        strutinsertframetitlestrutpar

        {

            ifxinsertframesubtitle@empty

            else

            {usebeamerfont{framesubtitle}usebeamercolor[fg]{framesubtitle}insertframesubtitlestrutpar}

            fi

        }

        vskip-1ex

        if@tempswaelsevskip-.3cmfi    end{beamercolorbox}%

}

defth@mystyle{%

    normalfont % body font

    setbeamercolor{block title example}{bg=orange,fg=white}

    setbeamercolor{block body example}{bg=orange!20,fg=black}

    definserttheoremblockenv{exampleblock}

  }

 %%% %%%%%%%

  setbeamertemplate{section in sidebar}{vbox{%

    beamer@sidebarformat{4pt}{section in sidebar}{insertsectionhead}}}

setbeamertemplate{section in sidebar shaded}{vbox{%

    beamer@sidebarformat{3pt}{section in sidebar shaded}{insertsectionhead}}}

makeatother





AtBeginSubsection

{

  begin{frame}<beamer>

    frametitle{initfamily Outline}

    tableofcontents[currentsection,currentsubsection]

  end{frame}

}







begin{document}



tikzstyle{every picture}+=[remember picture]

tikzstyle{na} = [baseline=-.5ex]



everymath{displaystyle}





begin{frame}

  frametitle{initfamily Outline}

  tableofcontents[pausesections]



end{frame}





begin{frame}

end{frame}



end{document}