\documentclass[a5paper]{article}
\usepackage[margin=5mm]{geometry}
\usepackage{tikz}
\usepackage{adjustbox}
\newcommand{\customgrid}{%
\begin{tikzpicture}[scale=0.55, font=\footnotesize\ttfamily]
% Draw the 12x31 grid
\draw (0,0) grid (12,31);
% Add numbers 1 to 31 on the left side
\foreach \y in {1,2,...,31}{
\node[anchor=east] at (-0.3,31.5-\y) {\y};
}
% Add first letters of months at the top
\foreach \x/\month in {1/J,2/F,3/M,4/A,5/M,6/J,7/J,8/A,9/S,10/O,11/N,12/D}{
\node[anchor=south] at (\x-0.5,31.2) {\month};
}
% Draw 10 squares with labels on the right side
\foreach \y in {0,1,...,9}{
% Draw the square
\draw[line width=0.2pt] (13,30-\y*3) rectangle (14,29-\y*3);
% Add the label
\node[anchor=west] at (14.2,29.5-\y*3) {Item \the\numexpr\y+1\relax};
}
\end{tikzpicture}
}
\begin{document}
\begin{adjustbox}{center}
\begin{minipage}[c][\textheight][c]{\textwidth}
\centering
% Shift content slightly to the right by adding horizontal space
\vspace*{0pt} % Optional vertical space adjustment
\hspace*{5mm} % Shift right by 5mm
\customgrid
\end{minipage}
\end{adjustbox}
\end{document}
