breakable box with varwidth

Question

PROBLEM

Build an environment to put some text in some boxes that should be both breakable across a page and adapt to text width. Unfortunately, packages mdframed and tcolorboxes have the first option, but not the second, because it seems that varwidth makes them uncomfortable.

PROPOSED SOLUTION

Build two environments.

WORKING EXAMPLE

\documentclass{article}
    % General document formatting
    \usepackage[margin=0.7in]{geometry}
    \usepackage[parfill]{parskip}
    \usepackage[utf8x]{inputenc}
    \usepackage{lmodern,textcomp}
    \usepackage[italian]{babel}
    % Related to math
    \usepackage{amsmath,amssymb,amsfonts,amsthm}

    % just for this example
    \usepackage{blindtext}

    % lists
    \usepackage{enumerate}
    \renewcommand{\labelitemii}{$\ast$}
    \renewcommand{\labelitemiii}{--}

    % colors
    \usepackage{xcolor}
    \definecolor{myblue}{RGB}{0,32,155}
    \definecolor{myred}{RGB}{192,0,0}
    \definecolor{mygray}{RGB}{68,84,106}
    \definecolor{myred2}{RGB}{180,4,38}
    \definecolor{myorange}{RGB}{238,132,104}
    \definecolor{mygreen}{RGB}{26,152,80}

    % url
    \usepackage{hyperref}

    % useful comments
    \usepackage{varwidth}
    \usepackage{mdframed}

    \mdfdefinestyle{basemdstyle}{%
        skipabove=1em,
        skipbelow=1em,
        innertopmargin=0.75em,
        innerbottommargin=0.75em
        }
        \newmdenv[style=basemdstyle]{baseemph}

    % breakable 
    \newcommand\lredemph[1]{%
            \begin{baseemph}[fontcolor=myred]%
                {#1}%
            \end{baseemph}}

    % width-adaptive
    \newcommand\redemph[1]{\fbox{%
            \begin{varwidth}{\textwidth}%
                {\textcolor{myred}{#1}}%
            \end{varwidth}%
        }\par}


\begin{document}

\Blindtext

\lredemph{\textbf{this will go across pages.} \Blindtext}

\redemph{this will be just as large as the text}

\end{document}

Answer 1

comments added inline

\documentclass{article}
    % General document formatting
    \usepackage[margin=0.7in]{geometry}
    \usepackage[parfill]{parskip}
% avoid utf8x use utf8 on old latex releases,   use nothing on current releases \usepackage[utf8x]{inputenc}
    \usepackage{lmodern}
% not needed in current releases textcomp
    \usepackage[italian]{babel}
    % Related to math
    \usepackage{amsmath,amssymb,amsfonts,amsthm}

    % just for this example (not very Italian:-)
    \usepackage{blindtext}

    % lists
    \usepackage{enumerate} % I wrote this, but enumitem is better
    \renewcommand{\labelitemii}{$\ast$}
    \renewcommand{\labelitemiii}{--}

    % colors
    \usepackage{xcolor}
    \definecolor{myblue}{RGB}{0,32,155}
    \definecolor{myred}{RGB}{192,0,0}
    \definecolor{mygray}{RGB}{68,84,106}
    \definecolor{myred2}{RGB}{180,4,38}
    \definecolor{myorange}{RGB}{238,132,104}
    \definecolor{mygreen}{RGB}{26,152,80}

    % url
    \usepackage{hyperref}

    % useful comments
    \usepackage{mdframed}

    \mdfdefinestyle{basemdstyle}{%
        skipabove=1em,
        skipbelow=1em,
        innertopmargin=0.75em,
        innerbottommargin=0.75em
        }
        \newmdenv[style=basemdstyle]{baseemph}

    % breakable 
%if the text takes multiple lines use mdframed otherwise fbox
    \newcommand\lredemph[1]{%
\setbox0\vbox{{#1\par}}%
\ifdim\ht0>\baselineskip
            \begin{baseemph}[fontcolor=myred]%
                #1%
            \end{baseemph}%
\else
   \fbox{\textcolor{myred}{#1}}%
\fi}



\begin{document}

\Blindtext

\lredemph{\textbf{this will go across pages.} \Blindtext}

\lredemph{this will be just as large as the text}

\end{document}