Hi @catwingz,
It seems you do not need a child theme. Just do following:
1. Add a text widget in Promotion Headline Right Widget Area
2. Add following code in that Text Widget in ‘Text’ tab:
<a class="promotion-button mobile" href="tel:123456789">123456789</a>
<a class="promotion-button desktop" href="http://distresseddebt1.com/">123456789</a>
Here, you can make 123456789 to your number in tel:123456789. The 123456789 between and is text, whatever you write here, will be displayed as text. The desktop link http://distresseddebt1.com/ can be changed to anything you like as well.
2. Add following code in Appearance- Customize- Additional CSS box:
@media only screen and (max-width:768px) {
#promotion-message .promotion-button.desktop{
display: none;
}
}
@media only screen and (min-width:768px) {
#promotion-message .promotion-button.mobile{
display: none;
}
}
This should work. Let me know if you have trouble.
Regards,
Pratik