documentclass{beamer}
    usepackage[utf8]{inputenc}
    usepackage[T1]{fontenc}
    usepackage{graphicx}
    graphicspath{{Images/}}
    title{This is my short title that looks nice...}
    date[]{today}
    author[My name]{My name hfill texttt{My email} \[.5em] My affiliation}

    usetheme{mine}

    begin{document}

    begin{frame}
    titlepage
    end{frame}

    begin{frame}{Context}
        Test frame
    end{frame}

    end{document}

mode<presentation>

    setbeamertemplate{background}{
      begin{tikzpicture}
      useasboundingbox (0,0) rectangle(thepaperwidth,thepaperheight);
      % Top box.
      fill[color=green!20!black!90] (0,2) rectangle (thepaperwidth,        thepaperheight);
      % Left box.
      fill[color=green!20!black!90] (0,0) rectangle(2.95,1.9);
      % Right box.
      fill[color=green!20!black!90] (3.05,0) rectangle(thepaperwidth,1.9);
      % Makes page white if not on page 1 (i.e. title page).
      ifnumthepage>1relax%
       fill[white,opacity=1] (0,0) rectangle(thepaperwidth,thepaperheight);
       fi
      end{tikzpicture}
    }

    setbeamertemplate{items}[square]
    setbeamertemplate{sections/subsections in toc}[square]

    % Title page
    defbeamertemplate*{title page}{mine}[1][]
    {
       vskip5.5cm%
        begin{beamercolorbox}[wd=12cm,leftskip=3cm,#1]{title page header}
          usebeamerfont{title}inserttitle%
        end{beamercolorbox}%
        vskip0.25cm%
        begin{beamercolorbox}[wd=12cm,leftskip=3cm,#1]{date}
          usebeamerfont{author}insertdate%
        end{beamercolorbox}
        vskip1.2cm%
        begin{beamercolorbox}[wd=12cm,leftskip=3cm,#1]{author}
          usebeamerfont{author}insertauthor%
        end{beamercolorbox}
      vfill
    }