I'm making a colored table for a time planning exercise. I made a specialrule since \midrule were too close to the activities. Spacing is now functional but the cells are not getting colored wholly. How can I color the entire cell?
\documentclass[12pt]{article}
\usepackage[table]{xcolor}
\usepackage{booktabs}
\newcommand{\thinrule}{\specialrule{0.045 ex}{0.07 ex}{0.19 ex}}
\colorlet{mark}{black!25}
\newcommand*{\z}{\cellcolor{mark}}
\newcommand*{\mc}[2]{\multicolumn{#1}{c}{#2}}
\newcommand*{\y}[1]{\multicolumn{1}{c}{#1}}
\begin{document}
\begin{tabular}{p{0.55\textwidth}*{4}{p{3em}}}
\toprule
& \mc{4}{Month} \\
\cmidrule{2-5}
\mc{1}{Activity} &\y{1} &\y{2}&\y{3}&\y{4} \\
\midrule
Foo1 & \z & & & \\ \thinrule
Foo2 & \z & & & \\ \thinrule
Foo3 & \z & \z & & \\
\bottomrule
\end{tabular}
\end{document}
