I'm attempting to customize the appearance of pinned columns in MUI's DataGrid by adding a column header-row divider.
The official demo by MUI for pinned columns [https://codesandbox.io/s/qix39o?file=/demo.tsx] displays the pinned column header without a bottom outline similar to this, but I want it to resemble the header-row divider seen on other non-pinned columns like this (Please note the faint gray divider line near the bottom of the screenshot).
If anyone can provide guidance on which CSS classes and properties to modify, it would be greatly appreciated!
UPDATE: For further clarification, you can view a side-by-side comparison picture here. enter image description here
UPDATE: Success! Please refer to my response below. Any suggestions or feedback are also welcome.