Change the background color, icon color, or icon color on hover.

CSS:

Background color:
#cff .cff-share-tooltip{ background: yellow; }

Icon color:
#cff .cff-share-tooltip a { color: red !important;}

Icon color on hover:
#cff .cff-share-tooltip a:hover {color: blue !important;}

Change to rgb, rgba or hex color for the background
Color for the icon
Color for the icon with the visitor hovers over with the mouse