Remove the highlight part of Header Newsletter Button when Hover hovered

Site URL: https://www.thesocialflair.co/

In the newsletter block of my footer, when you hover over the "Sign up" button, the text is highlighted with black which I want to remove. I want the background to be completely white while the text is black. Please help!!

Here is the custom CSS on my page right now

.site-wrapper{background: linear-gradient(#DACEC4, #CEAA9A, #947B73)!important;}

.page-section, .section-background{background:transparent!important;}

footer,
footer *
 {
 background-color: black!important;
}
footer.sections input {
    background-color: white !important;
}

footer.sections button.newsletter-form-button * {
    color: white;
}

Hi,

I see 2 buttons on homepage content & footer is fine.

Which button are you referring to?