The problem of multi-level subscripts

<img width="217" height="167" alt="Image" src="https://github.com/user-attachments/assets/035f7dd6-fbe8-4c82-9b97-f68d8bc6baaf" />
当有多级下标时，如图，二级下标的位置太靠下了，且字体大小与一级下标一样，无法调节。
When there are multiple levels of subscripts, as shown in the figure, the position of the second-level subscript is too low, and the font size is the same as that of the first-level subscript, which cannot be adjusted.