\documentclass{article}
\usepackage{xcolor}
\usepackage{framed}
\begin{document}
\section{Basics}
\begin{framed}
This is stuff that's framed.
\end{framed}
Note that the \begin{framed}framed\end{framed} stuff is a block!
\begin{framed}
This is stuff that's framed.
And it can hold multiple paragraphs.
\end{framed}
\begin{framed}
And even stuff in multiple Paragraphs.
\paragraph{Does this work?} But not in LaTeXML!
\end{framed}
\section{Variants}
\begin{oframed}
This is stuff that's framed, but would stay open at page breaks.
This doesn't make so much sense for LaTeXML, so it's pretty much
the same.
\end{oframed}
\definecolor{shadecolor}{rgb}{0.5,0.75,0.5}
\begin{shaded}
This is stuff that's shaded green;
should fade into the margin, whatever that means.
\end{shaded}
\begin{shaded*}
This is stuff that's shaded green;
it should end sharply at the margin.
\end{shaded*}
\begin{snugshade}
This is stuff that's snugly shaded green;
fading into the margin.
\end{snugshade}
\begin{snugshade*}
This is stuff that's snugly shaded green;
ending sharply at the margin.
\end{snugshade*}
\begin{leftbar}
This is with a left bar, like a changebar?
\end{leftbar}
\definecolor{TFFrameColor}{rgb}{0.5,0.5,0.75}
\definecolor{TFTitleColor}{rgb}{1,1,1}
\begin{titled-frame}{A Titled Frame}
This is a titled frame.
\end{titled-frame}
\end{document}