Increasing the size of the navigation sidebar text in Beamer (Berkeley theme)

Question

How can I increase the size of the navigation sidebar in Beamer? I'm using the Berkeley theme.

I'd only like to change the size of the sections and subsections, keeping the subsection size smaller than the section size.

\documentclass[serif]{beamer}
\usetheme{Berkeley}
\usepackage[utf8]{inputenc}
\usepackage{mathpazo}

\makeatletter
\beamer@headheight=1.5\baselineskip

\newcommand\Fontvi{\fontsize{8}{10.2}\selectfont}

\title{}
\author{}
\date{\today}

\begin{document}

\logo{\color{blue!50}\scalebox{2}{unir}}

\frame
{
\begin{center}

\begin{figure}
    \centering
    \includegraphics[width=3cm]{UNIR-Logo.jpg}  
    \end{figure}

\textcolor[rgb]{0.00,0.50,1.00}{Universidad Internacional de La Rioja}\\
\vspace{0.32cm}

Trabajo fin de máster\\
\vspace{0.32cm}

\textcolor[rgb]{0.00,0.50,1.00}{One}\\
\vspace{0.32cm}

\Fontvi{
\begin{tabular}{|r|l|}
  \hline
  % after \\: \hline or \cline{col1-col2} \cline{col3-col4} ...
  Presentado por: & Xan \\
    \hline
 Fecha: & Marzo de 2.016 \\  
  \hline
\end{tabular}
}
\end{center}


}


\frame{\Fontvi{\tableofcontents}}

\section{Introducción}
\frame
{
Aquí estará el planteamiento del problema.
}
\subsection{Problema}
\frame
{
\frametitle{This is the second slide}
\framesubtitle{A bit more information about this}
}

\subsection{Justificación}
\frame
{
}

\subsection{Objetivos}
\frame
{
}

\section{Marco Teórico}
\frame
{
}

\subsection{Modelo Van Hiele}
\frame
{
}

\frame
{
}

\subsection{Modelo Vinner}
\frame
{
}

\subsection{Modelo Duval}
\frame
{
}

\subsection{Visualización y representación}
\frame
{
}

\subsection{Obstáculos a la enseñanza efectiva}
\frame
{
}

\section{Propuesta de Intervención}
\frame
{
}

\subsection{Actividad 1}
\frame
{
}

\subsection{Actividad 2}
\frame
{
}

\subsection{Actividad 3}
\frame
{
}

\subsection{Actividad 4}
\frame
{
}

\subsection{Actividad 5}
\frame
{
}

\section{Conclusiones}
\frame
{
}

\subsection{Conclusiones-Discusión}
\frame
{
}

\subsection{Limitaciones y prospectiva}
\frame
{
}


\end{document}

Answer 1

The space above the vertical navigation is usually reserved for the title and the author of the presentation. But these are not visible in your MWE because you didn't set them. You want a stripped version of the sidebar with just the navigation? You can do that by adding the following lines to your preamble:

\makeatletter
\setbeamertemplate{sidebar left}{\insertverticalnavigation{\beamer@sidebarwidth}}
\makeatother

Output:

---

EDIT:

I read your question again. And now I'm not so sure if I understood you right. The arrow in the image does not reflect what you want? You actually want to increase the font sizes of the sections and subsections in the sidebar? This is possible with these two commands.

\setbeamerfont{section in sidebar}{size=\scriptsize}
\setbeamerfont{subsection in sidebar}{size=\tiny}

You can use any predefined font size or \fontsize{•}{•} if you need a custom font size.

If you increase these font sizes you probably also want to slightly increase the width of the sidebar.

\usetheme[width=3\baselineskip]{Berkeley}