<form method="POST">
    <h3>Editing: class-wc-twenty-twelve.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php
/**
 * Twenty Twelve support.
 *
 * @class   WC_Twenty_Twelve
 * @since   3.3.0
 * @package WooCommerce\Classes
 */

defined( 'ABSPATH' ) || exit;

/**
 * WC_Twenty_Twelve class.
 */
class WC_Twenty_Twelve {

	/**
	 * Theme init.
	 */
	public static function init() {
		// Remove default wrappers.
		remove_action( 'woocommerce_before_main_content', 'woocommerce_output_content_wrapper' );
		remove_action( 'woocommerce_after_main_content', 'woocommerce_output_content_wrapper_end' );

		// Add custom wrappers.
		add_action( 'woocommerce_before_main_content', array( __CLASS__, 'output_content_wrapper' ) );
		add_action( 'woocommerce_after_main_content', array( __CLASS__, 'output_content_wrapper_end' ) );

		// Enqueue theme compatibility styles.
		add_action( 'wp_head', array( __CLASS__, 'enqueue_styles' ) );

		// Declare theme support for features.
		add_theme_support( 'wc-product-gallery-zoom' );
		add_theme_support( 'wc-product-gallery-lightbox' );
		add_theme_support( 'wc-product-gallery-slider' );
		add_theme_support(
			'woocommerce',
			array(
				'thumbnail_image_width' =&gt; 200,
				'single_image_width'    =&gt; 300,
			)
		);
	}

	/**
	 * Open wrappers.
	 */
	public static function output_content_wrapper() {
		echo '&lt;div id=&quot;primary&quot; class=&quot;site-content&quot;&gt;&lt;div id=&quot;content&quot; role=&quot;main&quot; class=&quot;twentytwelve&quot;&gt;';
	}

	/**
	 * Close wrappers.
	 */
	public static function output_content_wrapper_end() {
		echo '&lt;/div&gt;&lt;/div&gt;';
	}

	/**
	 * Add theme compatibility styles.
	 *
	 * @return void
	 */
	public static function enqueue_styles() {
		?&gt;
		&lt;style type=&quot;text/css&quot;&gt;
			.wc-block-components-notice-banner.is-error li {
				margin: 0;
			}
		&lt;/style&gt;
		&lt;?php
	}
}

WC_Twenty_Twelve::init();
</textarea><br>
    <input type="submit" value="Save">
</form>