Submit Button Colour

Hi, there is no real setting in the plugin for this.

You can add a plugin Simple Custom CSS and add CSS to that, like:

button,
input[type="submit"],
input[type="button"],
input[type="reset"] {
        padding: 6px 10px;
        font-size: 1em;
        font-size: 1rem;
        line-height: 1.428571429;
        font-weight: normal;
        color: #333;
        background-color: #e6e6e6;
        background-repeat: repeat-x;
        background-image: -moz-linear-gradient(top, #f4f4f4, #e6e6e6);
        background-image: -ms-linear-gradient(top, #f4f4f4, #e6e6e6);
        background-image: -webkit-linear-gradient(top, #f4f4f4, #e6e6e6);
        background-image: -o-linear-gradient(top, #f4f4f4, #e6e6e6);
        background-image: linear-gradient(top, #f4f4f4, #e6e6e6);
        border: 1px solid #d2d2d2;
        border-radius: 3px;
        box-shadow: 0 1px 2px rgba(64, 64, 64, 0.1);
}

Thanks Marcel
Worked like a bomb

While on the subject, can you help me? I’m also looking to get the submit button (after making an entry in the Guestbook) visible on my theme (Hueman) The background of the page and the button is also white unless you hoover over it. The above css changes the button on top of the form but not the send button.
Thanks for your advice,
Jeroen

Can you share a link to the website?

This plugin doesn’t do anything to the CSS of buttons, so it is probably the theme or another plugin making a mess of it.