How can I highlight this item of an enumerated list?

Question

How could I hightlight an item from an enumerated list just like this is from the following picture?

enter image description here

\documentclass[12pt,a4paper]{article} 
\usepackage{enumerate} 
\usepackage{tikz} 
\usepackage{mdframed} 
\usepackage{type1cm} 
\usepackage{lettrine} 
\usepackage[listings]{tcolorbox} 
\usepackage{color} 
\begin{document} 
\begin{enumerate} 
\item 12 
\item 143 
\item 154 
\end{enumerate} 
\end{document}

A minimal working code be this one above.

@Jubobs: I don't think it's duplicated. In the current form the question is unclear. Giannis: Please provide a minimal working example. — Marco Daniel, Apr 07 '13 at 16:50
related: http://tex.stackexchange.com/questions/56435/replace-item-with-myitem-to-box-each-list-member-with-an-mdframed — Marco Daniel, Apr 07 '13 at 16:56
@giannis Please edit your question to include your MWE; do not post it in a comment. — jub0bs, Apr 07 '13 at 17:06
I guess Enumerated text and formula with background color might help you. :) — Claudio Fiandrino, Apr 07 '13 at 17:07
I think this one is pretty relevant: Box around a few items in an itemize environment — cmhughes, Apr 07 '13 at 17:52
@cmhughes: a tikzmark answer I wasn't aware of: thanks for pointing this. :) — Claudio Fiandrino, Apr 07 '13 at 18:04
@giannis can you confirm if the link I provided works for you? — cmhughes, Apr 07 '13 at 18:27
@cmhughes it might work. I'm gonna try it! thank you all very much! — Y_gr, Apr 07 '13 at 19:28

score 1 · Answer 1 · answered Apr 07 '13 at 18:07

If the lists are as simple that the one you have shown a rather easy solution is to define your own \item commands. One for highlighting and one for no highlighting.

\documentclass[12pt,a4paper]{article} 
\usepackage{xcolor,soul} 
\begin{document}
\makeatletter
\renewcommand\theenumi{\@Roman\c@enumi.}
\long\def\Item#1\par{%
 \stepcounter{enumi}%
 \leavevmode\makebox[2em]{\theenumi} #1%
 \vskip4\p@ \@plus2\p@ \@minus\p@
}
\long\def\hItem#1\par{%
 \stepcounter{enumi}%
 \leavevmode\makebox[2em]{\hl\theenumi}\hl{ #1}%
 \vskip4\p@ \@plus2\p@ \@minus\p@
}
\newenvironment{hlroman}{\quote\setcounter{enumi}{0}}
{\endquote}

\begin{hlroman}
\hItem A\par
\Item B\par
\Item C\par
\end{hlroman}
\end{document}

Feel free as an exercise to improve, by adding \leftkskip, \rightskip or hangindent to suit. Add complexity as needed (see for sample source2e 228).

I have used the soul package for highlighting.

How can I highlight this item of an enumerated list?

1 Answers1