Hello,
1. I have a bit changed your custom code http://prntscr.com/itntji. Please clear cache and check now.
2. You can use this custom css code:
.single-product .page-heading {
display: none;
}
3. You can make changes in theme files (woopress/woocommerce folder) via child theme – https://codex.wordpress.org/Child_Themes
or use custom css code to hide some elements on single product page. This article will be useful for removing tabs – https://docs.woocommerce.com/document/editing-product-data-tabs/ (add code in functions.php file of child theme)
Regards