beamerposter 标题的背景和脚注

Question

我怎样才能给这个投影仪标题添加灰色背景和黑色脚注？

编辑：这是一个编译的 MWE

\documentclass{beamer}
\usepackage[size = custom, height = 110, width = 81]{beamerposter}
\definecolor{darkred}{RGB}{175,1,1}
\setbeamertemplate{headline}{
 \leavevmode
  \begin{columns}
   \begin{column}{\linewidth}
    \vskip2cm
    \centering
    \usebeamercolor{title in headline}{\color{darkred}\VERYHuge{\textbf{\inserttitle}}\\[1.5ex]}
    \vskip2cm
  \end{column}
   \vspace{1cm}
  \end{columns}
}
\title{A Rhapsody in Foo}
\begin{document}
  Foo.
\end{document}

Answer 1

可以通过 添加背景beamercolorbox，通过 添加脚注线rule。

\documentclass{beamer}
\usepackage[size = custom, height = 110, width = 81]{beamerposter}
\definecolor{darkred}{RGB}{175,1,1}
\setbeamercolor{headline}{fg=black,bg=gray!30}

\setbeamertemplate{headline}{
    \leavevmode
    \begin{beamercolorbox}[wd=\paperwidth]{headline}%
    \begin{columns}
        \begin{column}{\linewidth}
            \vskip2cm
            \centering
            \usebeamercolor{title in headline}{\color{darkred}\VERYHuge{\textbf{\inserttitle}}\\[1.5ex]}
            \vskip2cm
        \end{column}
        \vspace{1cm}
    \end{columns}
    \rule{\paperwidth}{10pt}
    \end{beamercolorbox}
}
\title{A Rhapsody in Foo}
\begin{document}
    Foo.
\end{document}