Override functions in functions.php (here universal_customizer_styles)

Hi Joe,

I am playing with your theme and I really like it for its accessibility level.

One small thing that could make it more modular: in functions.php, would it be possible to add before each function an “if not exists”:

if ( ! function_exists( 'theme_special_nav' ) ) {
    function theme_special_nav() {
        //  Do something.
    }
}

(as it is suggested in Using functions.php in child themes)

My exact need is that I want to disable the universal_customizer_styles() in order to specify the colors only in my CSS (and only there, without possible override).

What do you think about it ? Is there a clever way ? Thanks !
Matthieu