Cannot change border-color

Hey,

Having some issues with styling my contact form.

I want to add a border color of green when hovering over the button. (like the other buttons on the page).

When I add border-color: it doesnt seem to work.

Here is my CSS:

input.wpcf7-form-control.wpcf7-submit {
background-color: #4CA31A;
border-color: #4CA31A;
font-size: 21px;
width: 100%;
border-radius: 4px;
padding: 15px 22px;
}

input.wpcf7-form-control.wpcf7-submit:hover {
background-color: #FFFFFF;
border-color: #4CA31A;
color: #4CA31A;
font-size: 21px;
width: 100%;
border-radius: 4px;
padding: 15px 22px;
}

Here is the page: https://speechangel.com/contact-private/

(The contact form in question has just an email field above a button)

Anyone have any ideas what the issue is?

Thanks,

Neil

https://www.ads-software.com/plugins/contact-form-7/