Modal box: cannot change header color, stays white

[pls note that site is not live] Hi, I have been having an issue with the modal box since almost 2 years. I cannot change color on the header to transparent. It is white and stays white. The only reason I need the header is because you can’t have a top close button without also enabling the header. How can I change the color please, the settings are not working. I have cleared cache, etc.. many times, restart, refresh, no change. CSS also doesn’t work, in my case trying separately using using: premium-modal-box-close-button-container or premium-modal-box-modal-header with: {
background-color: #fff0 !important;
} Please help, thank you. https://imgur.com/a/hXpBYgS