Center text on mobile

Hello, I have searched online and on this forum for a solution to this problem and have tried a variety of the solutions previously offered to no avail. I am trying to center the “Call xxx-xxx-xxxx to talk to an expert” text on https://chaampmarketing.com/refinance-with-thompson-kane/. I’ve tried the mobile css styles box in the widget itself, I have a custom css plugin that allows for page-specific css styling, and I’ve tried the Appearance > Custom CSS entry as well. Here is a sample of what I’ve tried, but honestly I’ve tried dozens of variations of this and other stuff I’ve found online:

@media all and(max-width:480px){
#phoneheader .textwidget h3 {
text-align: center !important;
}
}

I appreciate any help.

Thanks,
Phil