Hello,

Our theme’s advanced typography settings allow the change in the font and typography. You are not getting it right.

Please try adding the following Custom CSS in the Custom CSS for Mobile area under Theme Settings >> Custom CSS.

.wd-tab-wrapper h2 {
    font-size: 20px;
}

It will change the heading size for mobile devices. But if you put in Custom CSS for the Desktop area it will change for Desktop.

Best Regards