Option Tree integration of Custom CSS

Question

I would love to integrate Custom CSS field from my Option Tree plugin to the code, but if I try to integrate them following way into functions.php, it ends up with Fatal error: Call to undefined function ot_get_option() in /data/web/virtuals/51889/virtual/www/domains/demo.kybernaut.cz/ommo-wp/wp-content/themes/ommo/functions.php on line 36 So it looks like that I call the function before loading ot_get_option function from Option tree, is that possible? What to do with it? Thanks a lot!

//Custom CSS
    if (ot_get_option('css', false) != false) {
        function css() {
            return '<style>'.ot_get_option('css').'</style>';   
        }
        add_action( 'wp_head', 'css', 100 );
    }

Answer 1

never* execute code outside of hooks as you are more likely to call a function or use a variable before they were declared and initialized.

your code should be

function css() {
    if (ot_get_option('css', false) != false) {
            echo'<style>'.ot_get_option('css').'</style>';   
        }
    }

add_action( 'wp_head', 'css', 100 );

*never say never, but this is a rule to follow unless you have a very explicit reason to ignore it.