WP_Customize_Custom_CSS_Setting::value()

	public function value() {
		if ( $this->is_previewed ) {
			$post_value = $this->post_value( null );
			if ( null !== $post_value ) {
				return $post_value;
			}
		}
		$id_base = $this->id_data['base'];
		$value = '';
		$post = wp_get_custom_css_post( $this->stylesheet );
		if ( $post ) {
			$value = $post->post_content;
		}
		if ( empty( $value ) ) {
			$value = $this->default;
		}

		/** This filter is documented in wp-includes/class-wp-customize-setting.php */
		$value = apply_filters( "customize_value_{$id_base}", $value, $this );

		return $value;
	}