Created attachment 178980 [details]
In Options > LibreOffice > Application Colors > Scheme, you can tell the app to use the "LibreOffice Dark" color scheme, which is great, except that the comments in Writer look wrong as they still float on a light gray background. They should be on some color that is either slightly darker or slightly lighter than the "Document background" #333333 color.
Created attachment 179037 [details]
Looks good on Windows
In Windows, version 7.3 it looks good.
I would advise you to specify your LibO version, and DE so that it can verified by someone else.
Created attachment 179191 [details]
Looks good on macOS 10.15
Version: 188.8.131.52 / LibreOffice Community
Build ID: a69ca51ded25f3eefd52d7bf9a5fad8c90b87951
CPU threads: 8; OS: Mac OS X 10.15.7; UI render: default; VCL: osx
Locale: en-GB (en_FR.UTF-8); UI: en-US