Slicer Search Formatting - Desktop vs Service

I have a large, multi-tab report that's primarily governed by a few core slicers.  These rely on a search bar in tandem with a list (for example, to narrow choices from thousands of accounts).  The font color for the search bars is black, and for the lists is white as the slicers are set on a dark background.  These have had no issues for ~7 months and have not been changed.

Beginning yesterday, the font color for the search bars (which cannot be independently set via the dropdowns) continued to show in black for the desktop version, but once published the service version began picking up the font color property of the lists.  I confirmed this by changing the list font and it was reflected in the search bar.

I attempted to use JSON (at which I'm admittedly bad) to fix this, based on suggestions best represented here.  However, I tried a few variations (including below) and no matter how narrowly I tried to define the property being set, most visuals (including everything from card fonts to chart colors) took on distorted colors.  

{
	"name": "slicer search box color setting",

	"visualStyles": {
		"slicer": {
			"*": {
				"smallLabel": [
					{
						"fontColor": { "solid": { "color": "#000000" } }
					}
				]
			}
		}
	}
}

Has anyone else seen difference between Desktop and Service and been able to deal with it?  If the answer lies in JSON, are there suggestions on how to limit the scope of the changes to slicer search fonts rather than all visuals somehow being impacted?

Thanks all,