\begin{tikzpicture}[
    arrow/.style={->, >=latex},
    font=\small
]
    % Add rotated Calibration text
    \node[rotate=90] at (-8.5,0) {\Large {\bf Calibration}};

    % Draw the outer dashed box for Calibration with light gray fill
    % \draw[dashed, ] (-8,-3.5) rectangle (10,3.2);
    \draw[dashed, fill=gray!10] (-8,-2.6) rectangle (1,2.8);
    \draw[dashed, fill=gray!10] (2,-2.6) rectangle (10,2.8);
    % \node at (5.75,2.5) {Calibration};
    
    % Position step 1 and step 2 with more space between them
    \node (step1) at (-3.5,0) {\input{gps-overview-figure/cal/step1}};
    \node (step2) at (6,0) {\input{gps-overview-figure/cal/step2}};
    
    \node[below=0.1cm of step1,  align=center] {\large 1. Collect augmented calibration samples};
    \node[below=0.1cm of step2,  align=center] {\large 2. Calibrate $\hat{f}$ on $(X_i, K_i)$ pairs using CP};
    % Add raw arrow between coordinates with thicker line
    \draw[->, >=latex, line width=4pt] (1,0) -- (2.8,0);
    
    % Add step labels at the bottom
    % \node at (4,-1.5) {1. Collect Calibration Samples};
    % \node at (9,-1.5) {2. Calibrate $\hat{f}$ on $(X_i, K_i)$ pairs using CP to obtain $\hat{K}$};
    
    % Add legend at the bottom
\end{tikzpicture}
