How to change color of infolines and frame title

\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}

\begin{frame}
\frametitle{A test frame}
\end{frame}

\end{document}

The same could have been achieved with:
\setbeamercolor*{palette tertiary}{bg=Brown}
\setbeamercolor{frametitle}{fg=Brown,bg=Brown!20}