An added note on the box shadow. I see that there are some macOS specific styles to use the OS's box shadow. Also box shadows are in place for Proton on panels - so it seems like they should be there. For the time being, I'll move the patch to review to fix the border color for Light theme. If needed, we can file a separate bug for any adjustments to the box shadow.
Bug 2050256 Comment 5 Edit History
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An added note on the box shadow - I see that there are some macOS specific styles to use the OS's box shadow. Also box shadows are in place for Proton on panels - so it seems like they should be there. For the time being, I'll move the patch to review to fix the border color for Light theme. If needed, we can file a separate bug for any adjustments to the box shadow.