Change color for just one icon?

Instead of black, the Steam icon is appearing as a dark gray color that makes it hard to see with my site background (https://www.samanthalienhard.com/). I’m not sure if this is a problem with the icon or if I just never noticed it before, although I thought it had displayed right when I first added it.

Is there a way for me to customize the color of just that one icon? If I change the color, all of them change.

Thanks!

https://www.ads-software.com/plugins/simple-follow-me-social-buttons-widget/