Hello @combove,

To change the color of the background color of the shopping cart title use below given CSS.

For this go to Admin Panel > Appearance > Customize > Additional CSS and paste below given CSS.

table.shop_table.cart thead {
    background: #000;
}

You can change the hex color code according to your requirement .

Hope this helps.

If you need any assistance further, please let us know.

Best Regards!!