Visibility issue with diff view buttons

[x100ex]

After the recent update, diff control buttons no longer change color (from black to blue) to show the active state. Instead, they just become bold, which is very hard to see. The old color-based system was much clearer.

The last version with the clear color‑based scheme (black for off, blue for on) was v2.63.

[DanPristupov]

They do change the color. The accent color is used, but since it's dark gray, you don't see it.

[x100ex]

I checked again.
Under Sequoia, the color has indeed changed from a constant blue to the 'accent colour'.
However, under BigSur, for some reason, the system settings dont seem to affect these buttons.