CambridgeUS 主题中的水平阴影框架标题

Question

我想（尽可能简单地）修改框架的框架标题颜色，但不更改其他任何内容：我目前使用 CambridgeUS 主题，基本上我想修改我的框架标题颜色，就像 Warsaw 主题中一样。我将我当前的代码和图像加入其中，向您展示我到底想要什么。

颜色错误但主题很好：

    \documentclass{beamer}

    \usepackage[latin1]{inputenc}
    \usepackage[T1]{fontenc}
    \usepackage[francais]{babel}

    \definecolor{rougefonce}{RGB}{180,1,1}
    \definecolor{bleufonce}{RGB}{30,1,135}
    \definecolor{vertfonce}{RGB}{0,90,0}
    \definecolor{bleuleger}{RGB}{220,220,235}
    \definecolor{rougeleger}{RGB}{235,220,220}
    \definecolor{vertleger}{RGB}{220,235,220}
    \definecolor{bleutitre}{RGB}{0,0,80}
    \definecolor{bleuroi}{RGB}{0,0,180}

    \usetheme{CambridgeUS}
    \usecolortheme{whale}

    \setbeamercolor{frametitle}{fg=white, bg = bleutitre}
    \setbeamercolor{author in head/foot}{bg = black, fg = white}
    \setbeamercolor{title in head/foot}{bg = bleufonce, fg = white}
    \setbeamercolor{date in head/foot}{bg = bleuroi, fg = white}
    \setbeamercolor{section in head/foot}{bg = black, fg = white}

    \usefonttheme[onlymath]{serif}
    \title{Test with wrong color}
    \author{Bob}
    \date{\today}
    \institute{}

    \begin{document}
    \section{Test}
    \begin{frame}{Wrong color}
    \maketitle
    \end{frame}



    \end{document}

颜色正确但主题错误：

    \documentclass{beamer}

    \usepackage[latin1]{inputenc}
    \usepackage[T1]{fontenc}
    \usepackage[francais]{babel}

    \usetheme{Warsaw}
    \usefonttheme[onlymath]{serif}
    \title{Test with right color}
    \author{Bob}
    \date{}
    \institute{}

    \begin{document}
    \section{Test}
    \begin{frame}{Right color}
    \maketitle
    \end{frame}

    \end{document}