Hello Leon,
To change the column upper layer background color on hover I would suggest you add this custom CSS code Column —>Customize —>Element CSS
$el.x-col:hover .x-bg-layer-upper-color {
background-color: rgb(5 5 5 / 79%) !important;
}
Please feel free to change the background color as per your design. The purpose of providing custom CSS is to show you how to add CSS code to your site. Writing custom CSS is outside the scope of our theme support. If you need more customization, you need to learn CSS and learn how to use the browser’s element inspector.In case if you have no idea about coding you can subscribe to One where customization questions are answered.
Hope it helps.
Thanks