Get rid of pop-up content after user subscribes

Site URL: https://www.licenter.org/

I'm wondering if it's possible to get rid of the content "sign up for our newsletter..." after a user subscribes and only "thank you!" be visible. I'm sure it's a simple fix I'm just not finding but I don't see any options under content, etc. TIA

Add to Home > Design > Custom CSS

[data-slice-id="5a4d1ac4e2c483daf9d41bf0"], [data-slice-id="5a4d1ac4e2c483daf9d41bef"] {
    display: none;
}