Header Media Title Font and Site Title Questions

Hello, We are trying to change the font family for the "Header Media Title", but it does not change when we update the font family within the "Font Family Options" section of "Theme Options". We tried to update it via CSS, but could not get it to work properly. Also, we are wondering if it's possible to center the "Site Title"? It does appear to be centered on mobile devices, but it is left-aligned on desktop. Again, we attempted to make this adjustment with CSS, but could not get it to work. Thank you!