Code: Select all
\let\svitem\item
\newcommand\difbox[1]{\stackengine{0pt}{\color{gray!30}\rule{5ex}{1.15ex}}{%
\color{cyan!60!black}$\mkern1mu\makeballs{#1}$}{O}{c}{F}{F}{L}}
\def\makeballs#1{\ifnum#1>0\relax{\bullet}%
\expandafter\makeballs\the\numexpr#1-1\relax\fi}
\newenvironment{benumerate}
{\renewcommand\item[1][1]{\def\difficulty{##1}\svitem}%
\def\labelenumi{\smash{\stackunder[1pt]{\color{cyan!60!black}%
\bfseries\sffamily\theenumi}{\difbox{\difficulty}}}}%
\enumerate}{\endenumerate}
Thanks.