beamerposter 和 orem 环境中发生了什么

Question

如果我编译

\documentclass{beamer}
%\usepackage[scale=4]{beamerposter}
\makeatletter
\setbeamertemplate{theorem begin}
{
  {\color{blue}\inserttheoremheadfont% \bfseries
  \inserttheoremname
  \ifx\inserttheoremaddition\@empty\else\ (\inserttheoremaddition)\fi%
  :} \normalfont
}
\setbeamertemplate{theorem end}{%
 }
\makeatother
\begin{document}
\begin{theorem}
qqq
\end{theorem}
\end{document}

theorembody 是正常的。但是，如果我用 beamerposter 编译

\documentclass{beamer}
\usepackage[scale=4]{beamerposter}
\makeatletter
\setbeamertemplate{theorem begin}
{
  {\color{blue}\inserttheoremheadfont% \bfseries
  \inserttheoremname
  \ifx\inserttheoremaddition\@empty\else\ (\inserttheoremaddition)\fi%
  :} \normalfont
}
\setbeamertemplate{theorem end}{%
 }
\makeatother
\begin{document}
\begin{theorem}
qqq
\end{theorem}
\end{document}

theorembody 是斜体的！为什么？如何修复它？

Answer 1

获得直立字体的快速方法：

\documentclass{beamer}
\usepackage[scale=4]{beamerposter}
\makeatletter
\setbeamertemplate{theorem begin}
{
  {\color{blue}\inserttheoremheadfont% \bfseries
  \inserttheoremname
  \ifx\inserttheoremaddition\@empty\else\ (\inserttheoremaddition)\fi%
  :} \normalfont\upshape
}
\setbeamertemplate{theorem end}{%
 }
\makeatother
\begin{document}
\begin{theorem}
qqq
\end{theorem}
\end{document}