For those who are not aware there is now an option of having Document colours in font, highlight and background colours.
Document colours is a palette made up from the colours that are already in the document.
This is a huge asset, long overdue and will save those of us who use colours quite a bit of time
Several times in the recent past RedHat has changed the default palette of its version of LibreOffice
so for older files that need further work, all the outdated colours had either to be
rebuilt from scratch and used as custom colours or the closest available found from the new palette.