in beamer, change fontsize of selected slides with nested lists
Here's a \ChangeItemFont
command allowing you to change the font for the three valid nesting levels in an itemize environment, defined in the beamer
way; the syntax is
\ChangeItemFont{<font commands 1st level>}{<font commands 2nd level>}{<font commands 3rd level>}
The code and an example with some crazy font sizes in the first frame, just for illustration:
\documentclass{beamer}
\usepackage{lmodern}
\makeatletter
\newcommand\ChangeItemFont[3]{%
\renewcommand{\itemize}[1][]{%
\beamer@ifempty{##1}{}{\def\beamer@defaultospec{#1}}%
\ifnum \@itemdepth >2\relax\@toodeep\else
\advance\@itemdepth\@ne
\beamer@computepref\@itemdepth% sets \beameritemnestingprefix
\usebeamerfont{itemize/enumerate \beameritemnestingprefix body}%
\usebeamercolor[fg]{itemize/enumerate \beameritemnestingprefix body}%
\usebeamertemplate{itemize/enumerate \beameritemnestingprefix body begin}%
\list
{\usebeamertemplate{itemize \beameritemnestingprefix item}}
{\def\makelabel####1{%
{%
\hss\llap{{%
\usebeamerfont*{itemize \beameritemnestingprefix item}%
\usebeamercolor[fg]{itemize \beameritemnestingprefix item}####1}}%
}%
}%
\ifnum\@itemdepth=1\relax
#1%
\else
\ifnum\@itemdepth=2\relax
#2%
\else
\ifnum\@itemdepth=3\relax
#3%
\fi%
\fi%
\fi%
}
\fi%
\beamer@cramped%
\raggedright%
\beamer@firstlineitemizeunskip%
}}
\makeatother
\begin{document}
\begin{frame}
\frametitle{Font size changed}
\ChangeItemFont{\fontsize{30}{36}\selectfont}{\scriptsize}{\LARGE}
\begin{itemize}
\item First item.
\begin{itemize}
\item First subitem.
\begin{itemize}
\item First subsubitem.
\item Second subsubitem.
\item Third subsubitem.
\item Fourth subsubitem.
\end{itemize}
\item Second subitem.
\end{itemize}
\item Second item.
\item Third item.
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Regular font size}
\begin{itemize}
\item First item.
\begin{itemize}
\item First subitem.
\begin{itemize}
\item First subsubitem.
\item Second subsubitem.
\item Third subsubitem.
\item Fourth subsubitem.
\end{itemize}
\item Second subitem.
\end{itemize}
\item Second item.
\item Third item.
\end{itemize}
\end{frame}
\end{document}