Some beamer themes such as Berlin, Warsaw use shadow environment for theorems, definitions, proofs. How can I get rid of it and have the same look as in CambridgeUS for example?
[Tex/LaTex] Shadow blocks in Beamer
beamerthemes
Related Solutions
Personally, I don't like presentations with dark backgrounds since my eyes get tired too soon, but that's just a personal opinion. The beamer theme matrix shows a number of color themes that will give you dark backgrounds; for example:
\documentclass{beamer}
\usetheme{Warsaw}
\usecolortheme{beetle}
\begin{document}
\begin{frame}
\frametitle{Test Frame}
text
\end{frame}
\end{document}
or
\documentclass{beamer}
\usetheme{Warsaw}
\usecolortheme{fly}
\begin{document}
\begin{frame}
\frametitle{Test Frame}
text
\end{frame}
\end{document}
If you want to design your own, you can for example look at those color themes (they are in the directory /usr/local/texlive/2011/texmf-dist/tex/latex/beamer/themes/color in a typical TeX Live2011 installation) and make your adjustments. For example, here'sa variation on the fly color theme, but with a black background, as requested:
\documentclass{beamer}
\usetheme{Warsaw}
\setbeamercolor{normal text}{fg=white,bg=black!90}
\setbeamercolor{structure}{fg=white}
\setbeamercolor{alerted text}{fg=red!85!black}
\setbeamercolor{item projected}{use=item,fg=black,bg=item.fg!35}
\setbeamercolor*{palette primary}{use=structure,fg=structure.fg}
\setbeamercolor*{palette secondary}{use=structure,fg=structure.fg!95!black}
\setbeamercolor*{palette tertiary}{use=structure,fg=structure.fg!90!black}
\setbeamercolor*{palette quaternary}{use=structure,fg=structure.fg!95!black,bg=black!80}
\setbeamercolor*{framesubtitle}{fg=white}
\setbeamercolor*{block title}{parent=structure,bg=black!60}
\setbeamercolor*{block body}{fg=black,bg=black!10}
\setbeamercolor*{block title alerted}{parent=alerted text,bg=black!15}
\setbeamercolor*{block title example}{parent=example text,bg=black!15}
\begin{document}
\begin{frame}
\frametitle{Test Frame}
\framesubtitle{Test Frame}
Test
\begin{enumerate}
\item Test
\end{enumerate}
\begin{block}{Test}
Test
\end{block}
\end{frame}
\end{document}
Using text margin left=<length> and text margin right=<length> for \setbeamersize you can change the margins; in the example I set them both to 0pt just for illustration purposes:
\documentclass{beamer}
\setbeamersize{text margin left=0pt,text margin right=0pt}
\begin{document}
\begin{frame}
\begin{theorem}
text
\end{theorem}
\end{frame}
\end{document}
Best Answer
Using
you can get ride of the shadow around the boxes and redefining the
block titlecolor you can suppress the color for the title. An example: