framed box

startbox

\documentclass[10pt]{article}
\usepackage{fullwidth,lipsum,xcolor}
\RequirePackage{pgf}[2008/01/15]
\overfullrule0pt
\pgfkeys{/combo/.is family}
\makeatletter
\pgfkeys{/combo
    vrule-height/.store in=\vrule@height,
    vrule-height/.default=10pt,
    vrule-thickness/.store in=\vrule@thickness,
    vrule-thickness/.default=.4pt,
    hrule-thickness/.store in=\hrule@thickness,
    hrule-thickness/.default=0.4pt,
    text-color/.store in=\text@color,
    text-color/.default=black,
    rule-color/.store in=\rule@color,
    rule-color/.default=purple,
    left-padding/.store in=\left@padding,
    left-padding/.default=10pt,
    right-padding/.store in=\right@padding,
    right-padding/.default=10pt,
    top-padding/.store in=\top@padding,
    top-padding/.default=5pt,
    bottom-padding/.store in=\bottom@padding,
    bottom-padding/.default=5pt,
}
\def\setdefaults{\pgfkeys{/combo
    vrule-height,vrule-thickness,hrule-thickness,
    text-color, left-padding,right-padding,
    top-padding,bottom-padding,rule-color}%
}

\setdefaults
\newcommand\startbox[1][\setdefaults]{%
     \bgroup
     \pgfkeys{/combo #1}%
     \hfuzz\maxdimen\vfuzz\maxdimen
     \def\VR{\hskip-\parindent
      \vrule height\vrule@height width\vrule@thickness}%
     \leavevmode%
     {\color\rule@color%
     \hrule height\hrule@thickness depth0pt\relax%
     \vbox to -0.4pt{\VR}}%
     \vskip\top@padding%
     \leftskip\left@padding\relax
     \rightskip\right@padding\relax%
     
  }
\def\stopbox{%
     {\color\rule@color
     \vskip\bottom@padding
     \vskip-\vrule@height
     \hskip\dimexpr\hsize-\left@padding-\vrule@thickness\relax
     \VR
     \hrule width\hsize}%
     \egroup
\par
}

\begin{document}
Here is introductory text.

\begin{fullwidth}[outermargin = -3cm, width = \linewidth +3.0cm]
\startbox[vrule-height=12pt,bottom-padding=5pt,left-padding=10pt,right-padding=10pt]
    \lipsum[1-2]
\stopbox
\end{fullwidth}

Here is concluding text.\lipsum[1-2]
\startbox[vrule-height=12pt,bottom-padding=5pt,left-padding=30pt,right-padding=30pt]
    \lipsum[1-2]
\stopbox

\end{document}