%%
%% The LaTeX Companion, 3ed
%%
%% Example 8-4-14 on page I-621 in "Skins and styles --- altering the look and feel".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

%StartShownPreambleCommands
\usepackage[skins]{tcolorbox}
%StopShownPreambleCommands

\begin{document}
\scriptsize
\begin{tcolorbox}[widget,title=The widget skin]
  Provide some gradation in \tcblower
  background color and separation line.
\end{tcolorbox}
\end{document}