tcolorbox and table: adding a shadow to the table without padding

Question

I'm trying to apply a shadow to a longtabu environment (because I want the table expands to fit the available width), similar to this table (CSS):

But, for my sample LaTeX` table, between the shadow and the table, there's some border and padding and I don't know how to remove it:

\documentclass[11pt]{article}

\usepackage[spanish]{babel}
\usepackage[utf8]{inputenc}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}
\usepackage{geometry}
\usepackage{tabularx}
\usepackage{colortbl}
\usepackage[skins]{tcolorbox}
\usepackage{tabu}
\usepackage{longtable}

\definecolor{lightgray}{RGB}{180, 180, 180}

\geometry{
  a4paper,
  margin=1cm,
  top=1.3cm,
}

\begin{document}

\begin{tcolorbox}[enhanced,size=fbox,drop shadow]
  \begin{longtabu} to \textwidth {cXc}
    \rowcolor{Maroon}
    Imagen & Producto & Total\\
    \rowcolor{lightgray}
    A & B & C
  \end{longtabu}
\end{tcolorbox}

\end{document}

In short, I want to remove the borders, to center the shadow, and to remove the padding between the shadow and the table, preferably with using standard packages or environments, but using custom commands is also fine.

Answer 1

The solution was to put the table inside a TiKz node:

\begin{tikzpicture}
  \node[draw=none,shade,blur shadow={shadow blur steps=20, shadow xshift=0ex,shadow yshift=0ex, shadow blur radius=1ex},inner sep=0pt]
       {
         \begin{tabu}{>{\centering}m{0.2\textwidth}p{0.5\textwidth}>{\centering}p{0.2\textwidth}}
           \rowcolor{Maroon}
           \rowfont{\large\color{white}}
           & Producto & Total\\[0.8ex]
           \rowcolor{lightgray}
           \includegraphics[height=80px, width=0.18\textwidth,keepaspectratio]{icon.png} & B & J
         \end{tabu}
     };
\end{tikzpicture}