Need info for changes on Attributes tab for Map & Heat Maps
When using a dark theme, the label in the centre of a Speedometer is transparent. This allows for light colours to be used for the label text.
Guidelines for creating a dark theme
There is no guarantee ways to find out if text is inside, outside, partially inside the data blocks, so there is really only one way to make text labels work well in dark themes:
use dark application background
use dark colours for chart data
use light (e.g. white) text for chart data, which can be defined as per the screenshot below