Social icon resize but not email icon

Hi There,
Firstly new user, great product, thanks.

Problem resizing social icons in top bar:
Facebook, pinterest both resize using custom CSS as per:

The email icon (looks like fa-envelope ) however does not resize in the top bar.

any suggestions ?

PS Icons in the bottom bar as per above article work fine.
this discussion was started as google developer tests suggested icons too small (24x24) rather than (48x48) “Tap targets not sized appropriately” a small cross against SEO ranking!