Codex tools: Log in
The customize_controls_print_styles action hook is triggered within the <head></head> section of the theme customizer screen.
This hook functions similarly to the wp_head action hook, but only affects the theme customizer screen. Generally, when using the Theme Customization API, you are better off hooking into wp_head instead.
<?php add_action('customize_controls_print_styles', 'your_function'); ?>