Sticky Add to Cart Bar on Product Pages

add_action( 'wp_footer', function () {
    if ( ! function_exists( 'is_product' ) || ! is_product() ) {
        return;
    }

    $product = wc_get_product( get_queried_object_id() );

    if ( ! $product || ! $product->is_purchasable() || ! $product->is_in_stock() ) {
        return;
    }
    ?>
<div id="wpide-sticky-cart" hidden style="position:fixed;left:0;right:0;bottom:0;z-index:9998;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 16px;background:#fff;box-shadow:0 -2px 10px rgba(0,0,0,.12);">
    <span style="font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;"><?php echo esc_html( $product->get_name() ); ?></span>
    <span><?php echo wp_kses_post( $product->get_price_html() ); ?></span>
    <button type="button" class="button alt"><?php echo esc_html( $product->single_add_to_cart_text() ); ?></button>
</div>
<script>
(function () {
    var bar = document.getElementById('wpide-sticky-cart');
    var form = document.querySelector('form.cart');
    if (!bar || !form || !('IntersectionObserver' in window)) { return; }
    new IntersectionObserver(function (entries) {
        bar.hidden = entries[0].isIntersecting || entries[0].boundingClientRect.top > 0;
    }).observe(form);
    bar.querySelector('button').addEventListener('click', function () {
        form.scrollIntoView({ behavior: 'smooth', block: 'center' });
        var submit = form.querySelector('.single_add_to_cart_button');
        if (submit && form.classList.contains('cart') && !form.classList.contains('variations_form')) { submit.focus(); }
    });
})();
</script>
    <?php
} );