为什么我的定理下面的空间没有显示出来？

Question

我amsthm用 来设计我的定理mdframed。我尝试在定理之前和下方添加一些空间，skipabove如skipbelow所述这里在第 6 页。

\documentclass{article}

\usepackage{amsthm, mdframed}

\parindent 0pt
\definecolor{mygray}{gray}{0.95}

\mdfdefinestyle{mythm}{
    backgroundcolor=mygray,
    linewidth=0pt,
    innertopmargin=0pt,
    innerbottommargin=6pt,
    skipabove=20pt,
    skipbelow=20pt
}

\newmdtheoremenv[style=mythm]{thm}{Theorem}

\begin{document}
    This comes before the theorem.
    \begin{thm}
        This is my theorem.
    \end{thm}
    This comes after the theorem.
\end{document}

但是底部的间距并未显示出来。

出了什么问题？我该如何解决？

Answer 1

我已向作者发送了以下 MWE：

\documentclass{article}

\usepackage{amsthm, mdframed}

\definecolor{mygray}{gray}{0.95}

%
% notice how skipbelow is ignored
\mdfdefinestyle{mythm}{
    backgroundcolor=mygray,
    linewidth=0pt,
    innertopmargin=0pt,
    innerbottommargin=6pt,
    skipabove=5em,
    skipbelow=5em,
}

\newmdtheoremenv[style=mythm]{thm}{Theorem}

% if we use this instead, it works
% \mdfsetup{
%     backgroundcolor=mygray,
%     linewidth=0pt,
%     innertopmargin=0pt,
%     innerbottommargin=6pt,
%     skipabove=5em,
%     skipbelow=5em,
% }
% \newmdtheoremenv{thm}{Theorem}


\usepackage{kantlipsum}
\begin{document}
\kant*[2]
\begin{thm}
  This is my theorem.
\end{thm}
\kant*[2]
\end{document}