LibreOffice UI colors missing in Mint Cinnamon

I just installed Mint Cinnamon 19.1, which bundled LibreOffice The same version is bundled in a current installation of Kubuntu. In the Kubuntu installation (and all previous versions of LO I’ve used), there is an obvious color distinction in backgrounds between the menus/tools and the document work area.

For example, in Writer, the menu and tool ribbon across the top, the tool ribbon down the right side, the document scroll bar, and the information bar across the bottom have a light background. They frame a document work area, which has a darker background. The document is white. Above the document is the ruller, on which the area within the document margins is white and the area on the ends, outside the margins, matches the toolbar background.

In the Cinnamon installation, all of that distinction is missing. The entire application window has the same background color. There is also nothing delineating the top tool bar from the work area, This isn’t just a matter of missing color. The icon set is different, and the scroll bar is nearly invisible (no arrows top and bottom and no clear slider border; the long slider looks like a border and is nearly invisible).

Under Tools, Options, Application colors, everything is locked and there isn’t an obvious way to change anything. That, and the different stylizing of the icons and scroll bar would indicate that this reflects customizing for Cinnamon; some attempt at a uniform theme. I guess it’s supposed to look modern minimalist, but it degrade the usability. There also doesn’t appear to be a setting in the System Setting Control Center that affects this.

Is there a way to reset the UI colors to the LO standard?

I see that I could replace the bundled version with the Flatpak version, which is However, LO, itself, appears to have done somewhat the same UI degradation on v6.2. The web site images look like the menu is on a darker background, the scrollbar slider is more visible, and there are some faint lines separating the tool ribbons from the work area, but everything except the menu appears to have the same background color.

Is there a way to restore some color distinction in v6.2? And if I load v6.2, will it use standard LO colors, or will it adopt the Cinnamon theming?