Footer phone number doesn’t show on iPhone

My website:

estersohninc.com

This uses the Highend theme and a has a footer with a logo, address phone number and email, all on a white background. Everything looks perfect on all the web browsers I’ve seen, except Safari for iPhone. Here the phone number does not appear. A similar thread on this forum recommended adding the following string to the HIGHEND OPTIONS > GENERAL SETTINGS > CUSTOM CSS FIELD:

#hb-maintenance h4 a{
color: #fff;
}

I tried this and it does not work in my case.

I would appreciate any help you can provide. Thank you.

Glenn Estersohn