SVG graphics white and cannot be customised

Hi – you can see on this page:
https://honestcrust.enfield.kerchan.com/honest-stories/5-foods-that-you-can-forage-as-autumn-sets-in/
that I have 3 social icons on a blue background. I’d like to have them as black on a white background.

I’ve set the icons to black via the ‘theme selection’ settings but it doesn’t work.

Please help! great plug-in otherwise

The page I need help with: [log in to see the link]