Blue/Grey Night theme

[VDRainer]

Well, that’s how the core gauge works.
Something to read:

Change colors for gauge card?

The gauge card severity has only green, yellow and red. Every value lower than defined will be blue. BTW: Your links above show the same topic.

More intervals in Gauge

Only with the Custom gauge-card and a hack in the js file. Works very well and IMO looks better (smooth changes, value and name align) than the core gauge. No guarantee how long because Lovelace is constantly changing. The only issue, the gauge will not auto scale.