Add and retrieve a new typography field

Hello!

I’ve customized theme-options.php to add another changeable value.

For example i would like to change from Typography page (in Theme Settings) the background color of my header. So, in PHP file i’ve added the field that displays correctly on WP back-end.

Now i’ve this problem: how can I do to show the correct background-color to my header ID?

My header ID is called “cambiohead” and it is correctly declared in theme file header.php and in the style.css.

Thanks!