WooCommerce is aggressively pushing toward a modern web design future by replacing its classic shortcode-based checkout templates with the new, Gutenberg-powered WooCommerce Blocks. While the new Block Checkout is sleek and boasts higher conversion potential, it introduces a massive wave of layout and functional bugs for stores using older or highly customized themes.

Common manifestations of this bug include overlapping input fields, invisible text boxes where users cannot see what they are typing, missing terms and conditions checkboxes, and payment gateway icons rendering at massive, distorted sizes. This happens because old WordPress themes rely heavily on specific CSS classes linked to the legacy shortcode templates ([woocommerce_checkout]). When the new Blocks system renders a completely different HTML structure, the theme's styling rules fail to apply, or worse, clash violently, creating an unnavigable, broken UI that prevents customers from safely entering data.

The Solution

Depending on your development timeline, the solution involves either implementing custom CSS patches or rolling back to the ultra-stable classic checkout.

  1. The Quick Fix: Rollback to Legacy Shortcodes: If your site is currently losing money due to broken layout blocks, open your Checkout page in the WordPress editor. Delete the "Checkout Block." Add a new standard Shortcode Block and type:

    Plaintext
     
    [woocommerce_checkout]

    Do the same for your Cart page using [woocommerce_cart]. Save the pages. This instantly restores the time-tested layout that your theme natively supports.

  2. The Long-Term Fix: Enqueue Block-Specific Fixes: If you want to keep the modern blocks, you must fix the theme styling compatibility. Go to Appearance > Customize > Additional CSS and inject global layout reset properties to stabilize block inputs:

CSS
 
.wc-block-components-checkout-form .wc-block-components-text-input input {
    width: 100% !important;
    padding: 12px !important;
    color: #333333 !important;
}

  1. Update Theme & Extension Plugins: Ensure your theme developer has explicitly certified the theme as "Full Site Editing (FSE) & WooCommerce Blocks Compatible." If not, switch to a modern, block-first theme like Storefront or Blocksy.