%XeLaTeX
\documentclass{beamer}
%%%%%%%%%%%%%%%%%%%%%
\usepackage[orientation=landscape,size=a3,scale=4]{beamerposter}
%Adjust scale as you like. 

%dark mode
\newif\ifdarkmode
%\darkmodetrue%
%Definition of dark mode
\ifdarkmode
\definecolor{blackboardgreenB}{RGB}{35,75,35}
\definecolor{blackboardgreen}{RGB}{40,90,55}
\setbeamercolor{background canvas}{bg=blackboardgreen}
\setbeamercolor{normal text}{fg=white}
\setbeamercolor{block body}{fg=white,bg=blackboardgreenB}
\setbeamercolor{block title}{fg=yellow,bg=blackboardgreen}
\setbeamercolor{structure}{fg=white}
\setbeamercolor{alerted text}{fg=white}
\setbeamercolor{example text}{fg=white}
\def\pagenumbercolor{white}
\else
\def\pagenumbercolor{black}
\fi
%%The end of definition of dark mode

%For setting font (for XeLaTeX)
\usepackage{fontspec}
\usefonttheme{serif}
\setmainfont{Chalkboard}
\newfontfamily\handwriting{Chalkboard}
\newfontfamily\CB{Chalkboard}
\newfontfamily\CD{Chalkduster}
\newfontfamily\CM{Comic Sans MS}
%\usepackage{xeCJK}
%\setCJKmainfont{Hiragino Mincho ProN}
%%%%%%%%%%%%%%%%%%%%%
\setbeamertemplate{navigation symbols}{}
\setbeamertemplate{bibliography item}[text]
%%%%%%%%%%%%%%%%%%%%%
%Load packages
\usepackage{amsmath,amssymb,amsfonts}
\usepackage{tikz} 
\usetikzlibrary{calc,angles,quotes}
\usepackage{xcolor} 
\usepackage{eso-pic}
%
%Definition of page number command 
\newcommand{\pagenumber}{%
\AddToShipoutPictureFG*{%
\begin{tikzpicture}[remember picture,overlay]
\node[anchor=north east,font=\large,text=\pagenumbercolor] at ([xshift=-1cm,yshift=-1cm]current page.north east){\insertframenumber/\inserttotalframenumber};
\end{tikzpicture}%
}%
}
%The end of definition of page number command 
%
\begin{document}
\begin{frame}[c]
\begin{center}%Title
{\LARGE \bfseries 
{\CB This file is created by XeLaTeX}
}\\
\vspace{10pt}\
{\large 
Date
}\\
\vspace{10pt}
{\Large 
Author (Affiliation)
}
\end{center}
\vspace{20pt}
\begin{block}{Abstract}
{\CD An abstract should be concise and informative.}\\
\end{block}
\begin{block}{}
URL: \texttt{http://arxiv.nowhere.in.the.world}
\end{block}
\end{frame}

\begin{frame}[c]
\pagenumber
\begin{block}{This is a \TeX\ file for an A3 poster using \texttt{beamer}.}
\footnotesize 
The \texttt{beamerposter} package is loaded in the following line.
\begin{center}
\small $\backslash$\texttt{usepackage[orientation=landscape,size=a3,scale=3.2]\{beamerposter\}}
\end{center}
\texttt{landscape} specifies a landscape layout; changing it to \texttt{portrait} gives a portrait layout.\\
The \texttt{size} option allows A0-A4 to be specified, and changing the \texttt{scale} value changes the font size.\\
If this line is commented out, the document becomes an ordinary slide (128mm$\times$96mm) without the \texttt{beamerposter} package.
\end{block}
\begin{block}{Dark mode}
\footnotesize 
The following line activates dark mode. Commenting it out disables dark mode.
\begin{center}
\small $\backslash$\texttt{darkmodetrue}
\end{center}
In dark mode, the presentation is intended for projection, with a blackboard-coloured background and white text. Otherwise, it is intended for printing, with a white background and black text.

\end{block}

\begin{block}{The content is presented using \texttt{block} environments.}
\footnotesize 
If you would like to use a handwriting-style font, you can load one with XeLaTeX as follows.
\begin{center}
\begin{minipage}{0.49\textwidth}
$\backslash$\texttt{usepackage\{fontspec\}}\\
$\backslash$\texttt{newfontfamily$\backslash$CB\{Chalkboard\}\%font on Mac}\\
$\backslash$\texttt{newfontfamily$\backslash$CD\{Chalkduster\}\%font on Mac}\\
$\backslash$\texttt{newfontfamily$\backslash$CM\{Comic Sans MS\}}
\end{minipage}
\begin{minipage}{0.49\textwidth}
Example of a Japanese font setting\\
$\backslash$\texttt{usepackage\{xeCJK\}}\\
$\backslash$\texttt{setmainfont\{TeX Gyre Termes\}}
$\backslash$\texttt{setCJKmainfont\{Hiragino Mincho ProN\}\% Mac}
\end{minipage}
\end{center}
\end{block}
\tiny 
If you want to use a Japanese handwritten font, you may need to install and configure a suitable font first.
The fonts shown above may not be available on Windows; \texttt{Comic Sans MS} and \texttt{TeX Gyre Termes} should work.
Ask AI if you need help.
\end{frame}

\begin{frame}[c]
\pagenumber
\begin{block}{Problem}
The hard part is often finding the right question.
\end{block}
\vspace{10pt}
\begin{block}{Motivation}
The motivation in a paper need not be the motivation behind the discovery.
\end{block}
\begin{block}{Example}
Examples are often the first step toward a theory.
\end{block}
\begin{block}{Remark}
A paper should have a clear idea, not merely correct results.
\end{block}
\end{frame}

\begin{frame}[t]
\pagenumber
\begin{block}{Definition}
Formulating a good definition is not easy, but it is essential for building a sound theory.
\end{block}
\begin{block}{Definition}
The right definition often reveals the right theorem.
\end{block}
\begin{block}{Lemma}
This is a key lemma.
\end{block}
\begin{block}{Lemma}
Lemmas are often more important than theorems.
\end{block}
\end{frame}

\begin{frame}[c]
\pagenumber
\begin{block}{Main Theorem}
A main theorem should have a clear message.
\end{block}
\begin{block}{Proof}
A good proof should explain, not merely verify.
\end{block}
\vspace{100pt}
\begin{block}{Example}
\begin{itemize}
\item Examples do not merely illustrate a theory; they can lead to one.
\item A counterexample often reveals the essential hypothesis.
\end{itemize}
\end{block}
\end{frame}

\begin{frame}[c]
\pagenumber
\begin{block}{Main Theorem}
{\CD
\begin{itemize}
\item The statement below is correct.
\item The statement above is incorrect.
\end{itemize}
\vspace{20pt}
One cannot judge oneself accurately.}
\end{block}
\begin{block}{Proof}
\CD Contradiction!
\end{block}

\begin{block}{Corollary}
\CD One can prove anything from a contradiction!
\end{block}
\begin{block}{}
Many a writer of a mathematical
paper seems to be writing primarily to convince himself that his/her
theorem is correct, but not as an effort to communicate.\\
\hfill \href{https://arxiv.org/abs/1612.04888}{A Primer of Mathematical Writing}\\
\hfill by Steven Kunz
\end{block}
\end{frame}

\begin{frame}[c]
\pagenumber
\begin{block}{Application}
The best applications are often unexpected.
\end{block}
\vspace{60pt}
{ 
\setbeamercolor{block body}{bg=white, fg=black}
\begin{block}{Picture}
Insert pictures here.\\
A good picture is worth a thousand words. 
\end{block}
}
\end{frame}

\begin{frame}[c]
\pagenumber
\begin{block}{}
Your manuscript is both good and original; but the part that is good
is not original, and the part that is original is not good.\\
\hfill attributed to Samuel Johnson
\end{block}
\vspace{40pt}
\begin{block}{References}
\small 
\begin{thebibliography}{99}
\bibitem{A}
Reference A
\bibitem{B}
Reference B
\end{thebibliography}
\end{block}
\end{frame}
\end{document}