Mirroring ion-icon styles for Font Awesome Icons

Could anybody tell me how I can set the style of my font awesome icons so that they mirror the ion-icon, I assume there are sass variables I can use in my global.sass and just set my fa-icon to the same values but I can’t find any reference to anything of use?

I have managed to achieve what I need by adding the following to my global.sass

ion-content {
    fa-icon {
        color: rgba(var(--ion-text-color-rgb,0,0,0),0.54);
    }
}

this changes my fa-icon colours without affecting the colour of the selected icon in my tab bar once I wrap it in ion-content.

Not sure f there is a better solution to set all fa-icons to the desired colour without affecting the selected icon in the tab bar?