Not sure what specifically changed in the 1.16 update, but I'm unable to fix the plugin. At least with my current knowledge of CSS.
*THE 1.16 UI UPDATE CHANGED SOME THINGS THAT I WILL NEED TO UPDATE THE PLUGIN FOR. UNTIL THEN YOU SHOULDN'T USE THIS* I also just realized the images are derpy AF.
This purpose of this theme is to fix the enormous (and empty) header on entities with images.
It's most likely a very temporary fix, as the Kanka team will probably fix this issue soon enough.
This fix isn't perfect, though, due to the limitations of the CSS. Any entities without images will have a blank space where the plugin would have moved it to if it existed. Personally, if there has to be a gap, I prefer the it to be here (on underdeveloped entities, to boot) rather than at the top of my nice entities.
Of note, any resolutions other than maximized window 1080p will have issues with the image scaling when the campaign sidebar is opened. This can be fixed by editing a CSS value.
Also, entities with header images and/or both a location and normal tag will be suboptimal. This can be fixed by moving the image and entity sidebar down some more in the CSS.