LaTeX技巧327：用Tikz和ntheorem宏包制作精美定理环境

话不多说，先上图

代码如下

\documentclass[a4paper,10pt]{article}
\usepackage[svgnames]{xcolor}
\usepackage[framed]{ntheorem}
\usepackage{framed}
\usepackage{tikz}
\usetikzlibrary{shadows}
\newtheorem*{Theorem}{Theorem}
\theoremclass{Theorem}
\theoremstyle{break}

\tikzstyle{thmbox} = [rectangle, rounded corners, draw=black,
  fill=Cyan!20, inner sep=10pt, drop shadow={fill=black, opacity=1}]
\newcommand\thmbox[1]{%
  \noindent\begin{tikzpicture}%
  \node [thmbox] (box){%
    \begin{minipage}{.94\textwidth}%
      #1%
    \end{minipage}%
  };%
  \end{tikzpicture}}

\let\theoremframecommand\thmbox
\newshadedtheorem{ImportantTheorem}[Theorem]{Theorem}
\begin{document}
\section*{Theorems}
Text
\begin{ImportantTheorem}[Euler's identity]
The equality
\[ e^{\pi i} +1 = 0 \]
where $e$ is Euler's number, $\pi$ is the ratio of any circle's circumference
to its diameter and $i$ is the imaginary unit, is called \emph{Euler's identity}.
\end{ImportantTheorem}
\end{document}