As How to make Writer page adhere to system/LO theme? - #16 by TheSmallest states, LibreOffice, by default, modifies the document colour to adhere to the rest of the GUI, which itself adheres to the OS/DE-defined colouration.
However, #Base appears to have a few exceptions to this, because although its table views are as I expect them to be:
…its form views are not:
…at least, by default. Have I accidentally overriden something? Or is it now time for an FR to remediate this inconsistency? You can see exactly what I mean using How to delete record in a Join Table - #2 by Villeroy.