\begin{figure}[t]
% \captionsetup[subfigure]{labelformat=simple, labelsep=period}
% \renewcommand\thesubfigure{\alph{subfigure})} % 将子标题的标签格式改为 "a)"
  \centering
  \begin{subfigure}[b]{0.47\linewidth}   % PD:平衡一下图片大小，如果一样的图可以都用0.48
    \hspace{-3px} % PD: 往左挪点防止重心偏右
    \includegraphics[width=\linewidth]{assets/Layer10.pdf}
    % \includegraphics[width=\linewidth]{assets/Layer10_norubost.pdf}
    \caption{Across Head Dimensions}      % 子图标题留空即可自动生成 (a)
    \label{fig:attnindim}
  \end{subfigure}
  \hfill % 在两张图之间插入一个弹性空白，使它们左右对齐
  \begin{subfigure}[b]{0.48\linewidth}
    \hspace{-3px} % PD: 往左挪点防止重心偏右
    \includegraphics[width=\linewidth]{assets/AcrossLayer.pdf}
    \caption{Across Layers}
    \label{fig:attninlayer}
  \end{subfigure}
  \caption{Q-state activation strength visualizations in LLaMA-2-7B.
We compute the average L2 norm per attention head to quantify activation strength.
Stronger activations are concentrated in high-indexed (\ie low-RoPE frequency) dimensions and vary across layers, highlighting both dimension-wise and layer-wise heterogeneity.
}
  \label{fig:hotattn}
\end{figure}
% \py{font size of figure is too small}