Question: how to change the color of block in beamer?
Answer: \documentclass{beamer}
\usetheme{Warsaw}
\begin{document}
\begin{frame}
\setbeamercolor{block title}{use=structure,fg=white,bg=purple! 75! black}
\setbeamercolor{block body}{use=structure,fg=black,bg=white! 20! white}
\begin{block}{title 1}
...