highlight blocks beamer latex
\begin{frame}
\frametitle{Sample frame title}
In this slide, some important text will be
\alert{highlighted} because it's important.
Please, don't abuse it.
\begin{block}{Remark}
Sample text
\end{block}
\begin{alertblock}{Important theorem}
Sample text in red box
\end{alertblock}
\begin{examples}
Sample text in green box. The title of the block is ``Examples".
\end{examples}
\end{frame}