enumitem: How to Make Beamer Slides More Compact

Question

Here is an example TeX file using beamer to create a slideshow:

% Options for packages loaded elsewhere
\PassOptionsToPackage{unicode}{hyperref}
\PassOptionsToPackage{hyphens}{url}
\PassOptionsToPackage{dvipsnames,svgnames*,x11names*}{xcolor}
%
\documentclass[
  ignorenonframetext,
  aspectratio = 169]{beamer}
\usepackage{pgfpages}
\setbeamertemplate{caption}[numbered]
\setbeamertemplate{caption label separator}{: }
\setbeamercolor{caption name}{fg=normal text.fg}
\beamertemplatenavigationsymbolsempty
% Prevent slide breaks in the middle of a paragraph
\widowpenalties 1 10000
\raggedbottom
\setbeamertemplate{part page}{
  \centering
  \begin{beamercolorbox}[sep=16pt,center]{part title}
    \usebeamerfont{part title}\insertpart\par
  \end{beamercolorbox}
}
\setbeamertemplate{section page}{
  \centering
  \begin{beamercolorbox}[sep=12pt,center]{part title}
    \usebeamerfont{section title}\insertsection\par
  \end{beamercolorbox}
}
\setbeamertemplate{subsection page}{
  \centering
  \begin{beamercolorbox}[sep=8pt,center]{part title}
    \usebeamerfont{subsection title}\insertsubsection\par
  \end{beamercolorbox}
}
\AtBeginPart{
  \frame{\partpage}
}
\AtBeginSection{
  \ifbibliography
  \else
    \frame{\sectionpage}
  \fi
}
\AtBeginSubsection{
  \frame{\subsectionpage}
}
\usepackage{amsmath,amssymb}
\usepackage{lmodern}
\usepackage{iftex}
\ifPDFTeX
  \usepackage[T1]{fontenc}
  \usepackage[utf8]{inputenc}
  \usepackage{textcomp} % provide euro and other symbols
\else % if luatex or xetex
  \usepackage{unicode-math}
  \defaultfontfeatures{Scale=MatchLowercase}
  \defaultfontfeatures[\rmfamily]{Ligatures=TeX,Scale=1}
\fi
\usetheme[]{Nord}
% Use upquote if available, for straight quotes in verbatim environments
\IfFileExists{upquote.sty}{\usepackage{upquote}}{}
\IfFileExists{microtype.sty}{% use microtype if available
  \usepackage[]{microtype}
  \UseMicrotypeSet[protrusion]{basicmath} % disable protrusion for tt fonts
}{}
\makeatletter
\@ifundefined{KOMAClassName}{% if non-KOMA class
  \IfFileExists{parskip.sty}{%
    \usepackage{parskip}
  }{% else
    \setlength{\parindent}{0pt}
    \setlength{\parskip}{6pt plus 2pt minus 1pt}}
}{% if KOMA class
  \KOMAoptions{parskip=half}}
\makeatother
\usepackage{xcolor}
\IfFileExists{xurl.sty}{\usepackage{xurl}}{} % add URL line breaks if available
\IfFileExists{bookmark.sty}{\usepackage{bookmark}}{\usepackage{hyperref}}
\hypersetup{
  pdftitle={How Does the Eye Work},
  pdfauthor={Amar Al-Zubaidi},
  colorlinks=true,
  linkcolor={NordRed},
  filecolor={Maroon},
  citecolor={Blue},
  urlcolor={NordBlue},
  pdfcreator={LaTeX via pandoc}}
\urlstyle{same} % disable monospaced font for URLs
\newif\ifbibliography
\usepackage{longtable,booktabs,array}
\usepackage{calc} % for calculating minipage widths
\usepackage{caption}
% Make caption package work with longtable
\makeatletter
\def\fnum@table{\tablename~\thetable}
\makeatother
\setlength{\emergencystretch}{3em} % prevent overfull lines
\providecommand{\tightlist}{%
  \setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}
\setcounter{secnumdepth}{5}
\ifLuaTeX
  \usepackage{selnolig}  % disable illegal ligatures
\fi

\title{How Does the Eye Work}
\author{Amar Al-Zubaidi}
\date{\today}

\begin{document}
\frame{\titlepage}

\begin{frame}{The Process of Vision}
\protect\hypertarget{the-process-of-vision}{}
text

\begin{enumerate}
\tightlist
\item
  Light enters the eye through the cornea.

  \begin{enumerate}
  \tightlist
  \item
    When we look at an object, light that is reflected off of the object enters the eye through the cornea.
  \item
    The cornea bends the light before it passes through the aqueous humor.
  \end{enumerate}
\item
  The pupil adjusts in response to the light.
\item
  The lens focuses the light onto the retina.
\item
  The light is focused onto the retina.
\item
  The optic nerve transmits visual information to the brain.
\end{enumerate}
\end{frame}

\end{document}

I want to make one change:

1. remove the left margin for lists

   I can usually remove left margin for lists by using this code:

   \usepackage{enumitem}
   \setlist{leftmargin = *}
   

   But if I do that using beamer, I get this error:

   ! TeX capacity exceeded, sorry [grouping levels=255].
   \labelenumi ->{
                  \labelenumi }
   l.138 \end{frame}
   

How do I do this change?

Answer 1

The left margin for lists in beamer is controlled by the length \leftmargini, \leftmarginii etc.

\documentclass{beamer}

\settowidth{\leftmargini}{\usebeamertemplate{itemize item}}
\addtolength{\leftmargini}{\labelsep}

\addtolength{\leftmarginii}{-0.1cm}

\begin{document}

\begin{frame}
\frametitle{The Process of Vision}
text

\begin{enumerate}
\item
  Light enters the eye through the cornea.

  \begin{enumerate}
  \item
    When we look at an object, light that is reflected off of the object enters the eye through the cornea.
  \item
    The cornea bends the light before it passes through the aqueous humor.
  \end{enumerate}
\item
  The pupil adjusts in response to the light.
\item
  The lens focuses the light onto the retina.
\item
  The light is focused onto the retina.
\item
  The optic nerve transmits visual information to the brain.
\end{enumerate}
\end{frame}

\end{document}