How to edit css of form?

You just need to add the CSS styles you want to your style.css file inside your current theme folder.

Add an !important to the end of the sentences, so that it stands out, like this as an example:

.wysija-button{
 background-color: red !important;
}

I needed to find the right expression, but this worked just fine.
Thanks very much! ??

Sorry, there is a bit of a problem. This solution doesn’t seem to change the color on mobile.

You’ll have to check if your theme doesn’t use other stylesheets for your mobile version.

It’s a responsive theme so it only uses one stylesheet. I added the following but it didn’t change anything:
@media screen and (max-width: 600px) {
.wysija-submit{
background-color: red !important;
font-size: 22px !important;
}
}

solved it. thx

Cool, good to know!