// Source: https://github.com/WPTRT/code-examples/blob/master/customizer/sanitization-callbacks.php
// Reference: https://make.wordpress.org/themes/2015/02/10/custom-css-boxes-in-themes/
// Reference: http://mikejolley.com/2013/08/keeping-your-shit-secure-whilst-developing-for-wordpress/

function theme_slug_sanitize_css( $input ) {
	return wp_filter_nohtml_kses( $input );
}


/**
 * Sanitization: css 
 * Control: text, textarea 
 * 
 * Sanitization callback for 'css' type textarea inputs. This 
 * callback sanitizes $input for valid CSS.
 * 
 * NOTE: wp_strip_all_tags() can be passed directly as 
 * $wp_customize->add_setting() 'sanitize_callback'. It 
 * is wrapped in a callback here merely for example 
 * purposes.
 * 
 * @uses	wp_strip_all_tags()	https://developer.wordpress.org/reference/functions/wp_strip_all_tags/
 */
function theme_slug_sanitize_css( $input ) {
	return wp_strip_all_tags( $input );
}