beamerinnerthemeNXYZ.sty

\defbeamertemplate*{title page}{NicklasXYZ}{
    \vfill
    {
        \centering
        \usebeamerfont{title}\usebeamercolor[fg]{title}\inserttitle
        \par
    }
    \vskip 1cm
    {
        \centering
        \usebeamerfont{subtitle}\usebeamercolor[fg]{subtitle}\insertsubtitle
        \par
    }
    \vfill
}

% Set fonts
\setbeamerfont{title}{size=\Huge}
\setbeamerfont{subtitle}{size=\large}
\setbeamerfont{block title}{size=\normalsize}

\setbeamerfont{frametitle}{size=\Large}
\setbeamerfont{framesubtitle}{size=\small}

\setbeamerfont{itemize/enumerate body}{}
\setbeamerfont{itemize/enumerate subbody}{size=\scriptsize}
\setbeamerfont{itemize/enumerate subsubbody}{size=\scriptsize}

% Define base templates
\setbeamertemplate{navigation symbols}{}
\setbeamertemplate{description item}{\color{base-color-four!75!white}\hspace{0.25cm}\insertdescriptionitem}
\setbeamertemplate{itemize item}{\color{base-color-four!75!white}$\blacksquare$}

\setbeamertemplate{section in toc}[square]
\setbeamertemplate{subsection in toc}[square]