Hello,

The best option is to make the main header row as sticky: https://prnt.sc/1CviECE9dXzd , https://prnt.sc/LLqLSElXYbTq

Otherwise, you can add a custom CSS class to the element: https://prnt.sc/vqByV7kdM98O and then with the help of the code below, you can decrease that gap:

.single-product:has(.whb-sticked) .custom-product-column {
    margin-top: -45px;
}

Result: https://gyazo.com/72994548445b4d7c8a937dbd9a0be832

Unfortunately, we cannot provide the custom code via JS, because it’s beyond our limitations and support policy.

Let me know if you have any questions.

Kind Regards