# Changing the color of sections-subsections in the head


\documentclass[xcolor=dvipsnames]{beamer}
\usecolortheme[named=blue]{structure}

%------------------------\AtBeginSubsection[]----------------------
\AtBeginSubsection[]{
\transsplitverticalout
\tableofcontents[currentsection,currentsubsection]
\end{frame}
}

\title[The essential numerical range and the Olsen problem]{The
essential numerical range and the Olsen problem}
\author[{Student} (University of ....)]{Student}

\usepackage{tikz}

\colorlet{titleleft}{yellow!30!white}
\colorlet{titleright}{blue!30!black}

\setbeamercolor*{frametitle}{fg=blue!30!black}

\makeatletter
{\paperheight}{%
color(0pt)=(titleleft);
color(\paperwidth)=(titleright)}
\makeatother

%-----------------------------footline-----------------------------
\setbeamertemplate{footline}{
\leavevmode%
\hbox{%
\end{beamercolorbox}%
%            \hspace*{3em}
\end{beamercolorbox}%
\end{beamercolorbox}%
}%
\vskip0pt%
}

\begin{document}
\section{Introduction}
\section{Positive linear relations}
\section{Lattice linear relations}
\section{Domination by a positive compact relation.}
\subsection{Linear relation}
\subsection{Riesz spaces}
\begin{frame}{Linear relations}

\end{frame}

\end{document}


I want to change the frametitle as the style of {Student} (University of ....). Also I hope to change to colors of sections-subsections like the two colors of the foot.

With \colorlet{titleleft}{blue!30!black} \colorlet{titleright}{blue!30!black} \setbeamercolor*{frametitle}{fg=white} \setbeamercolor*{subsection in head/foot}{bg=yellow!30!white,fg=blue!30!black} you can achievce the following:

     \documentclass[xcolor=dvipsnames]{beamer}
\usecolortheme[named=blue]{structure}

%------------------------\AtBeginSubsection[]----------------------
\AtBeginSubsection[]{
\transsplitverticalout
\tableofcontents[currentsection,currentsubsection]
\end{frame}
}

\title[The essential numerical range and the Olsen problem]{The
essential numerical range and the Olsen problem}
\author[{Student} (University of ....)]{Student}

\usepackage{tikz}

\colorlet{titleleft}{blue!30!black}
\colorlet{titleright}{blue!30!black}

\setbeamercolor*{frametitle}{fg=white}

\makeatletter
{\paperheight}{%
color(0pt)=(titleleft);
color(\paperwidth)=(titleright)}
\makeatother

%-----------------------------footline-----------------------------
\setbeamertemplate{footline}{
\leavevmode%
\hbox{%
\end{beamercolorbox}%
%            \hspace*{3em}
\end{beamercolorbox}%
\end{beamercolorbox}%
}%
\vskip0pt%
}

\begin{document}
\section{Introduction}
\section{Positive linear relations}
\section{Lattice linear relations}
\section{Domination by a positive compact relation.}
\subsection{Linear relation}
\subsection{Riesz spaces}
\begin{frame}{Linear relations}

\end{frame}

\end{document}


For a more general approach, you might also be interested in defining your own colors. If you later want to change every blue element to have a different color, you only have to change one definition:

\colorlet{myblue}{blue!30!black}
\colorlet{myyellow}{yellow!30!white}
...

...
\colorlet{titleleft}{myblue}  %<----- left half of frame title background color
\colorlet{titleright}{myblue} %<----- right half of frame title background color
\setbeamercolor*{frametitle}{fg=white} %<---- Color of the frame title text

• Thank you very much for your great help. Please in general, If I want to change the color of the frametitle, what should I do? Thanks a lot. – Student Jul 20 '19 at 16:45
• @Student: Please see my edited answer for this. The background color of the frametitle is controlled by titleright and titleleft while {frametitle}{fg=... corresponds to the color of the frame title text. – leandriis Jul 20 '19 at 16:57
• Thank you for the details but perhaps you don't understand me very well. Please see my similar question:tex.stackexchange.com/questions/500753/… – Student Jul 20 '19 at 17:38

Sorry,

your question is not very clear.

Maybe, do you want this results?

         \documentclass[xcolor=dvipsnames]{beamer}
\usecolortheme[named=blue]{structure}

%------------------------\AtBeginSubsection[]----------------------
\AtBeginSubsection[]{
\transsplitverticalout
\tableofcontents[currentsection,currentsubsection]
\end{frame}
}

\title[The essential numerical range and the Olsen problem]{The
essential numerical range and the Olsen problem}
\author[{Student} (University of ....)]{Student}

\usepackage{tikz}

\colorlet{titleleft}{blue!30!black}
\colorlet{titleright}{blue!30!black}

\setbeamercolor*{frametitle}{fg=blue!30!white}

\makeatletter
{\paperheight}{%
color(0pt)=(titleleft);
color(\paperwidth)=(titleright)}
\makeatother

%-----------------------------footline-----------------------------
\setbeamertemplate{footline}{
\leavevmode%
\hbox{%
\end{beamercolorbox}%
%            \hspace*{3em}
\end{beamercolorbox}%
\end{beamercolorbox}%
}%
\vskip0pt%
}

\begin{document}
\section{Introduction}
\section{Positive linear relations}
\section{Lattice linear relations}
\section{Domination by a positive compact relation.}
\subsection{Linear relation}
\subsection{Riesz spaces}
\begin{frame}{Linear relations}

\end{frame}

\end{document}