on mobile onlyphone info font size

Dear support team,

My present programming allows me to hide the top header on large views. It should only be displayed on mobile views. Therefor I found this code:

/*phone info mobile only */
#header_meta {
    min-height: 60px !important; 
}
#header_meta .phone-info {
    line-height: 60px !important; 
    font-size: 20px !important; 
}

@media only screen and (min-width: 768px) {
#header_meta{
  display:none;
}
}

I cannot seem to get the phone info font bigger for mobile view.

Could you have a look please?

Thanks,
Stefan