Contact Form Button Color

Hello I found some code on this thread https://kriesi.at/support/topic/how-do-i-change-the-button-and-font-color-of-submit-button-in-contact-form/ to change the contact form button color. How would I also change the button hover color?

.main_color #submit, .main_color input[type=submit]{
background-color: red!important;
color: #fff!important;
border-color: red!important;
}