\environment back-0

\setupindenting[big]

\definecolumnset[two][n=3]
\definecolumnsetspan[test]

\definetextbackground[test]
  [background=color,
   backgroundcolor=gray]

\definetextbackground[more]
  [background=color,
   backgroundcolor=lightgray,
   alternative=1,rulethickness=2pt]

\dontcomplain

\starttext

\startcolumnset[two]

  \startcolumnsetspan[test]
    \input tufte
  \stopcolumnsetspan

  \starttextbackground[test]

  \input tufte \par

  \startnarrower

    \starttextbackground[more]

    \input tufte \par
    \input tufte \par
    \input tufte \par
    \input tufte \par
    \input tufte \par
    \input tufte

    \stoptextbackground

  \stopnarrower

  \stoptextbackground

  \input tufte

  \starttextbackground[more] \input tufte \stoptextbackground

  \starttextbackground[test] \input tufte \stoptextbackground

  \starttextbackground[more] \input tufte \stoptextbackground

\stopcolumnset

\stoptext