Very tiny issue - annoying border on the dock

[tillsbury]

So upgraded to Big Sur, working lovely so far. One tiny thing I can't understand though, there is a single-pixel border on the dock which on my iMac 2020 is dark grey (I'm in dark mode), and is fine. On my MacBook, though, it's a bright white border. Same dark mode, same wallpaper, as far as I can see all the same options in system preferences. Is there something I'm overlooking? The bright white border on the dock on my MacBook is a bit annoying, and it's so much subtler on the iMac. How do I change that?

 

[rssmll]

Go to Settings -> Accessibility -> Display. Then turn off "Reduce Transparency"