# Colour themes in beamer not working for lemma/theorem/definition environments

I'm currently trying to learn how to use beamer, and I have a presentation in a few days on red-black trees. For thematic reasons, I decided to go with the beaver colour scheme (as it gives me red and black as the main colours, which seemed fitting). However, for all the amsmath-defined environments (lemma, theorem, proof and definition), I still have blue headers with white text, instead of what I would expect from the beaver colour theme. What am I doing wrong? I've attached my minimal working example below.

\documentclass[onlymath]{beamer}

\mode<presentation>
{
\usetheme{Antibes}
\usecolortheme{beaver}
\setbeamercovered{transparent}
}

\usepackage[english]{babel}

\usepackage[latin1]{inputenc}

\usepackage{times}
\usepackage[T1]{fontenc}

\usepackage{tikz}

\usepackage{capt-of}

\usepackage{algorithm, float}
\usepackage[noend]{algpseudocode}
\usepackage{comment}

\title{Red-Black Trees}

\subtitle{Motivation, Description, Performance} % (optional)

\author {Kostya Ross}
\institute {AUT University}
\date {\today}

% If you have a file called "university-logo-filename.xxx", where xxx
% is a graphic format that can be processed by latex or pdflatex,
% resp., then you can add a logo as follows:

\pgfdeclareimage[height=1cm]{university-logo}{aut_logo.jpg}
\logo{\pgfuseimage{university-logo}}

\beamerdefaultoverlayspecification{<+->}

\begin{document}

\begin{frame}
\titlepage
\end{frame}

\begin{frame}{Motivation}{The sorted set problem}
\begin{lemma} %the title of this should be coloured as per beaver, but isn't for some reason
Something for testing.
\end{lemma}
\end{frame}

\end{document}


Am I crazy, or is this doable?

• is there a reason that your minimum example doesn't load amsthm? (i'd try it out, to check how beamer and amsthm interact, but without an example to start with, ...) – barbara beeton Oct 6 '13 at 14:46
• As I understood it, amsthm is already loaded by beamer. At least, this code lets me do everything I need it to do. – Koz Ross Oct 7 '13 at 20:56
• thanks for the information that amsthm is loaded by beamer. i didn't know that. (i've definitely used beamer, but not for anything that required "real" math.) looking through the code in the beamerbasetheorems.sty module, i see that some of the amsthm internals are redefined. so any alternations to those features has to take the redefinitions into account. guess i'll have to add beamer to the list of packages whose authors must be notified when the ams "math" packages change. in the meantime, it looks like you've got a good answer. – barbara beeton Oct 7 '13 at 21:33

The Antibes theme calls the orchid color theme. This sets the colors for the block environments (as seen in the beamercolorthemeorchid.sty), but the beaver color theme does not set those colors. So you have to do it by hand. The lines you could add (and edit to your liking) in your themes sections are

\setbeamercolor{block title}{use=structure,fg=white,bg=structure.fg!75!black}
\setbeamercolor{block title example}{use=example text,fg=white,bg=example text.fg!75!black}

\setbeamercolor{block body}{parent=normal text,use=block title,bg=block title.bg!10!bg}
\setbeamercolor{block body example}{parent=normal text,use=block title example,bg=block title example.bg!10!bg}


You are probably using the standard block most of the time. Here we see that the orchid theme uses the structure color, which is set by\setbeamercolor{structure}{fg=beamer@blendedblue} in the default color theme.

Long story short: Maybe you can just set the structure color to something that matches the theme. For example

 \setbeamercolor{structure}{fg=darkred}


Note that darkred is a color set within the beaver color theme.

This gives you slides like this:

And if you'd rather have a gray background for the body of the block, add something like:

\setbeamercolor{block body}{bg=gray!10!white}


to get this result:

• and a personal opinion: most people do not use the navigation on the bottom. You can turn it off to get less clutter on you slides. Just add \usenavigationsymbolstemplate{} in the header. – jens_bo Oct 6 '13 at 5:55