更改标题的字体颜色

Question

我想知道如何更改演示文稿标题的字体颜色吗？

我看见这里如何改变栏的颜色但不改变实际字体。

原始代码：

\documentclass[xcolor=dvipsnames]{beamer}
 \usetheme{CambridgeUS}
 \useinnertheme{rectangles}
 \useoutertheme{infolines}

 \setbeamercolor{frametitle}{fg=Brown,bg=Brown!20}
 \setbeamercolor{section in head/foot}{bg=Brown}
 \setbeamercolor{author in head/foot}{bg=Brown}
 \setbeamercolor{date in head/foot}{fg=Brown}

 \begin{document}

 \section{Font to be changed in the headline}
 \begin{frame}
 \frametitle{A test frame}
 \end{frame}

 \end{document}

编辑：回答之后，以下内容似乎对我不起作用

 \documentclass[xcolor=dvipsnames]{beamer}
 \mode<presentation>
 {
 \usetheme{AnnArbor}
 \setbeamercovered{transparent}
\useinnertheme{rounded}
   \usecolortheme{spruce}
 }

  \setbeamercolor{section in head/foot}{fg=White}


 \begin{document}

 \section{Font to be changed in the headline}
 \begin{frame}
 \frametitle{A test frame}
 \end{frame}

 \end{document}

我想保持主题原样，只想将标题的字体改为白色，否则难以阅读。

谢谢。

Answer 1

为适当的颜色模板添加fg（前景）规范；例如：

 \setbeamercolor{section in head/foot}{bg=Brown,fg=red}
 \setbeamercolor{subsection in head/foot}{bg=gray!30,fg=black}

完整示例：

\documentclass[xcolor=dvipsnames]{beamer}
\usetheme{CambridgeUS}
\useinnertheme{rectangles}
\useoutertheme{infolines}

\setbeamercolor{frametitle}{fg=Brown,bg=Brown!20}
\setbeamercolor{section in head/foot}{bg=Brown,fg=red}
\setbeamercolor{subsection in head/foot}{bg=gray!30,fg=black}
\setbeamercolor{author in head/foot}{bg=Brown}
\setbeamercolor{date in head/foot}{fg=Brown}

\begin{document}

\section{Font changed in the headline}
\begin{frame}
\frametitle{A test frame}
\end{frame}
\subsection{Font changed in the headline}
\begin{frame}
\frametitle{A test frame}
\end{frame}

\section{Font changed in the headline}
\begin{frame}
\frametitle{A test frame}
\end{frame}
\subsection{Font changed in the headline}
\begin{frame}
\frametitle{A test frame}
\end{frame}
 
\end{document}

最终的标题是：

更新

在对问题进行编辑后，

\documentclass[xcolor=dvipsnames]{beamer}
 \mode<presentation>
 {
 \usetheme{AnnArbor}
 \setbeamercovered{transparent}
\useinnertheme{rounded}
   \usecolortheme{spruce}
 }

  \setbeamercolor{section in head/foot}{fg=White}


 \begin{document}

 \section{Font to be changed in the headline}
 \begin{frame}
 \frametitle{A test frame}
 \end{frame}

 \end{document}

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