How to Change Form Button Style

This will do the text color and background...

input#wprevpro_submit_review {
color: #080808;
background-color: #ea143d;
}

Add this for the hover background...

input#wprevpro_submit_review:hover {
background: #c1c1c1;
}

Feel free to change the color codes. You can add the CSS to this field on the form settings...